diff --git a/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/platform-store.ts b/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/platform-store.ts
new file mode 100644
index 0000000..d2c266b
--- /dev/null
+++ b/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/platform-store.ts
@@ -0,0 +1,464 @@
+import { signal, type Reactive, type Unsubscribe } from '../../core/reactive.ts';
+import {
+  hasOwn,
+  requireArray,
+  requireInteger,
+  requireRecord,
+  requireString,
+  type ParsedLoginResponse,
+  type ParsedOnlinePayload,
+  type ParsedRoomResponse,
+  type ParsedSeatPayload,
+} from '../../protocol/contracts/index.ts';
+import type {
+  InsideRoomState,
+  PlatformPlayer,
+  PlatformState,
+} from './platform-types.ts';
+
+interface RoomBuildResult {
+  readonly players: PlatformState['players'];
+  readonly room: Extract<PlatformState['room'], { readonly kind: 'inside' }>;
+}
+
+function requirePositiveInteger(value: unknown, path: string): number {
+  const parsed = requireInteger(value, path);
+  if (parsed <= 0) throw new RangeError(`${path}: expected positive integer`);
+  return parsed;
+}
+
+function requireProtocolFlag(value: unknown, path: string): number {
+  const parsed = requireInteger(value, path);
+  if (parsed !== 0 && parsed !== 1) {
+    throw new RangeError(`${path}: expected protocol flag 0 or 1`);
+  }
+  return parsed;
+}
+
+function requireOnlineState(value: unknown, path: string): number {
+  const parsed = requireInteger(value, path);
+  if (parsed < 0 || parsed > 2) {
+    throw new RangeError(`${path}: expected onstate 0, 1, or 2`);
+  }
+  return parsed;
+}
+
+function parseRoomPlayer(value: unknown, path: string): {
+  readonly player: PlatformPlayer;
+  readonly isprepare: number;
+  readonly onstate: number;
+} {
+  const raw = requireRecord(value, path);
+  const isprepare = requireProtocolFlag(raw.isprepare, `${path}.isprepare`);
+  const onstate = requireOnlineState(raw.onstate, `${path}.onstate`);
+  const player: PlatformPlayer = {
+    playerid: requirePositiveInteger(raw.playerid, `${path}.playerid`),
+    nickname: requireString(raw.nickname, `${path}.nickname`),
+    avatar: requireString(raw.avatar, `${path}.avatar`),
+    ...(hasOwn(raw, 'ip') ? { ip: requireString(raw.ip, `${path}.ip`) } : {}),
+    isprepare,
+    onstate,
+  };
+  return { player, isprepare, onstate };
+}
+
+function recursivelyFreeze<T>(value: T, seen = new WeakSet<object>()): T {
+  if (typeof value !== 'object' || value === null) return value;
+  if (seen.has(value)) return value;
+  seen.add(value);
+  for (const child of Object.values(value)) recursivelyFreeze(child, seen);
+  return Object.freeze(value);
+}
+
+function buildRoom(
+  roomValue: unknown,
+  rawValue: unknown,
+  selfPlayer: PlatformPlayer,
+): RoomBuildResult {
+  const room = requireRecord(roomValue, '$.room');
+  const raw = requireRecord(rawValue, '$.raw');
+  const roomcode = requireString(room.roomcode, '$.room.roomcode');
+  const selfSeat = requireInteger(room.seat, '$.room.seat');
+  const roomtype = requireArray(room.roomtype, '$.room.roomtype');
+  const sourcePlayers = requireArray(room.players, '$.room.players');
+  if (requireString(raw.roomcode, '$.raw.roomcode') !== roomcode) {
+    throw new RangeError('$.room.roomcode: expected value parsed from raw roomcode');
+  }
+  if (requireInteger(raw.seat, '$.raw.seat') !== selfSeat) {
+    throw new RangeError('$.room.seat: expected value parsed from raw seat');
+  }
+  if (raw.roomtype !== roomtype) {
+    throw new RangeError('$.room.roomtype: expected canonical raw roomtype reference');
+  }
+  if (raw.players !== sourcePlayers) {
+    throw new RangeError('$.room.players: expected canonical raw players reference');
+  }
+  if (selfSeat < 0 || selfSeat >= sourcePlayers.length) {
+    throw new RangeError('$.room.seat: expected server seat index within players');
+  }
+
+  let stage: number;
+  if (hasOwn(raw, 'isbattle')) {
+    stage = requireProtocolFlag(raw.isbattle, '$.raw.isbattle');
+  } else if (hasOwn(raw, 'deskwar')) {
+    stage = requireProtocolFlag(raw.deskwar, '$.raw.deskwar');
+  } else {
+    throw new TypeError('$.raw: expected isbattle or deskwar');
+  }
+  const needprepare = requireProtocolFlag(raw.needprepare, '$.raw.needprepare');
+  const infinite = requireProtocolFlag(raw.infinite, '$.raw.infinite');
+
+  const seatPlayerIds: (number | null)[] = [];
+  const readySeats: number[] = [];
+  const offlineSeats: number[] = [];
+  const parsedPlayers = new Map<number, PlatformPlayer>();
+
+  for (let seat = 0; seat < sourcePlayers.length; seat += 1) {
+    const value = sourcePlayers[seat];
+    if (value === null) {
+      seatPlayerIds.push(null);
+      continue;
+    }
+    const parsed = parseRoomPlayer(value, `$.room.players[${seat}]`);
+    if (parsedPlayers.has(parsed.player.playerid)) {
+      throw new RangeError(`$.room.players[${seat}].playerid: duplicate player seat`);
+    }
+    parsedPlayers.set(parsed.player.playerid, parsed.player);
+    seatPlayerIds.push(parsed.player.playerid);
+    if (parsed.isprepare === 1) readySeats.push(seat);
+    if (parsed.onstate === 1) offlineSeats.push(seat);
+  }
+
+  if (seatPlayerIds[selfSeat] !== selfPlayer.playerid) {
+    throw new RangeError('$.room.players: self seat must contain the authenticated player');
+  }
+
+  recursivelyFreeze(roomtype);
+  const entities: Record<number, PlatformPlayer> = {};
+  for (const [playerid, parsedPlayer] of parsedPlayers) {
+    const player = playerid === selfPlayer.playerid
+      ? { ...selfPlayer, ...parsedPlayer }
+      : parsedPlayer;
+    entities[playerid] = Object.freeze(player);
+  }
+
+  return {
+    players: Object.freeze({
+      selfPlayerId: selfPlayer.playerid,
+      entities: Object.freeze(entities),
+    }),
+    room: Object.freeze({
+      kind: 'inside',
+      roomcode,
+      selfSeat,
+      seatPlayerIds: Object.freeze(seatPlayerIds),
+      readySeats: Object.freeze(readySeats),
+      offlineSeats: Object.freeze(offlineSeats),
+      roomtype,
+      stage,
+      needprepare,
+      infinite,
+    }),
+  };
+}
+
+function requireInsideRoom(state: PlatformState): InsideRoomState {
+  if (state.room.kind !== 'inside') {
+    throw new Error('room: expected player to be inside a room');
+  }
+  return state.room;
+}
+
+function parseSeatAction(value: ParsedSeatPayload): {
+  readonly seat: number;
+  readonly raw: Readonly<Record<string, unknown>>;
+} {
+  const input = requireRecord(value, '$.event');
+  const seat = requireInteger(input.seat, '$.event.seat');
+  const raw = requireRecord(input.raw, '$.event.raw');
+  if (requireInteger(raw.seat, '$.event.raw.seat') !== seat) {
+    throw new RangeError('$.event.raw.seat: expected the parsed seat');
+  }
+  return { seat, raw };
+}
+
+function requireOccupiedSeat(room: InsideRoomState, seat: number): number {
+  if (seat < 0 || seat >= room.seatPlayerIds.length) {
+    throw new RangeError('$.event.seat: expected room seat range');
+  }
+  const playerid = room.seatPlayerIds[seat];
+  if (playerid === null) {
+    throw new RangeError('$.event.seat: expected an occupied seat');
+  }
+  return playerid;
+}
+
+const INITIAL_STATE: PlatformState = Object.freeze({
+  app: Object.freeze({ phase: 'idle' }),
+  players: Object.freeze({
+    selfPlayerId: null,
+    entities: Object.freeze({}),
+  }),
+  room: Object.freeze({ kind: 'outside' }),
+});
+
+export type PlatformStateListener = (state: PlatformState, previous: PlatformState) => void;
+
+export class PlatformStore {
+  private readonly stateCell: Reactive<PlatformState> = signal(INITIAL_STATE);
+
+  getState(): PlatformState {
+    return this.stateCell.value;
+  }
+
+  subscribe(listener: PlatformStateListener): Unsubscribe {
+    return this.stateCell.subscribe(listener);
+  }
+
+  applyLoginSuccess(parsed: ParsedLoginResponse): void {
+    const input = requireRecord(parsed, '$.login');
+    const state = requireInteger(input.state, '$.login.state');
+    if (state !== 0) {
+      throw new RangeError('$.login.state: expected successful state 0');
+    }
+    const playerid = requireInteger(input.playerid, '$.login.playerid');
+    if (playerid <= 0) {
+      throw new RangeError('$.login.playerid: expected positive integer');
+    }
+    const raw = requireRecord(input.raw, '$.login.raw');
+    if (requireInteger(raw.playerid, '$.login.raw.playerid') !== playerid) {
+      throw new RangeError('$.login.raw.playerid: expected the parsed playerid');
+    }
+    const player: PlatformPlayer = Object.freeze({
+      playerid,
+      nickname: requireString(raw.nickname, '$.login.raw.nickname'),
+      avatar: requireString(raw.avatar, '$.login.raw.avatar'),
+      ip: requireString(raw.ip, '$.login.raw.ip'),
+    });
+    const roomResult = input.room === null
+      ? {
+          players: Object.freeze({
+            selfPlayerId: playerid,
+            entities: Object.freeze({ [playerid]: player }),
+          }),
+          room: Object.freeze({ kind: 'outside' as const }),
+        }
+      : buildRoom(input.room, raw, player);
+    this.stateCell.value = Object.freeze({
+      app: Object.freeze({ phase: 'logged-in' }),
+      players: roomResult.players,
+      room: roomResult.room,
+    });
+  }
+
+  replaceRoom(parsed: ParsedRoomResponse): void {
+    const input = requireRecord(parsed, '$.response');
+    if (requireInteger(input.state, '$.response.state') !== 0) {
+      throw new RangeError('$.response.state: expected successful state 0');
+    }
+    if (input.room === null || input.room === undefined) {
+      throw new TypeError('$.response.room: expected parsed room snapshot');
+    }
+    const previous = this.getState();
+    const selfPlayerId = previous.players.selfPlayerId;
+    if (selfPlayerId === null) {
+      throw new Error('players.selfPlayerId: expected authenticated player');
+    }
+    const selfPlayer = previous.players.entities[selfPlayerId];
+    if (selfPlayer === undefined) {
+      throw new Error('players.entities: missing authenticated player');
+    }
+    const roomResult = buildRoom(input.room, input.raw, selfPlayer);
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: roomResult.players,
+      room: roomResult.room,
+    });
+  }
+
+  clearRoom(): void {
+    const previous = this.getState();
+    requireInsideRoom(previous);
+    const selfPlayerId = previous.players.selfPlayerId;
+    if (selfPlayerId === null) {
+      throw new Error('players.selfPlayerId: expected authenticated player');
+    }
+    const selfPlayer = previous.players.entities[selfPlayerId];
+    if (selfPlayer === undefined) {
+      throw new Error('players.entities: missing authenticated player');
+    }
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: Object.freeze({
+        selfPlayerId,
+        entities: Object.freeze({ [selfPlayerId]: selfPlayer }),
+      }),
+      room: Object.freeze({ kind: 'outside' }),
+    });
+  }
+
+  playerJoin(parsed: ParsedSeatPayload): void {
+    const event = parseSeatAction(parsed);
+    const previous = this.getState();
+    const room = requireInsideRoom(previous);
+    if (event.seat < 0 || event.seat >= room.seatPlayerIds.length) {
+      throw new RangeError('$.event.seat: expected occupied room seat range');
+    }
+    if (room.seatPlayerIds[event.seat] !== null) {
+      throw new RangeError('$.event.seat: expected an empty seat');
+    }
+    const joined = parseRoomPlayer(event.raw, '$.event.raw');
+    if (room.seatPlayerIds.includes(joined.player.playerid)) {
+      throw new RangeError('$.event.raw.playerid: duplicate player seat');
+    }
+
+    const player = Object.freeze(joined.player);
+    const entities = Object.freeze({
+      ...previous.players.entities,
+      [player.playerid]: player,
+    });
+    const seatPlayerIds = [...room.seatPlayerIds];
+    seatPlayerIds[event.seat] = player.playerid;
+    const readySeats = joined.isprepare === 1
+      ? [...room.readySeats, event.seat]
+      : [...room.readySeats];
+    const offlineSeats = joined.onstate === 1
+      ? [...room.offlineSeats, event.seat]
+      : [...room.offlineSeats];
+
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: Object.freeze({
+        selfPlayerId: previous.players.selfPlayerId,
+        entities,
+      }),
+      room: Object.freeze({
+        ...room,
+        seatPlayerIds: Object.freeze(seatPlayerIds),
+        readySeats: Object.freeze(readySeats),
+        offlineSeats: Object.freeze(offlineSeats),
+      }),
+    });
+  }
+
+  playerReady(parsed: ParsedSeatPayload): void {
+    const event = parseSeatAction(parsed);
+    const previous = this.getState();
+    const room = requireInsideRoom(previous);
+    const playerid = requireOccupiedSeat(room, event.seat);
+    if (room.readySeats.includes(event.seat)) {
+      throw new RangeError('$.event.seat: player is already ready');
+    }
+    const player = previous.players.entities[playerid];
+    if (player === undefined) {
+      throw new RangeError('players.entities: occupied seat has no canonical player');
+    }
+    const entities = Object.freeze({
+      ...previous.players.entities,
+      [playerid]: Object.freeze({ ...player, isprepare: 1 }),
+    });
+    const readySeats = Object.freeze([...room.readySeats, event.seat]);
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: Object.freeze({
+        selfPlayerId: previous.players.selfPlayerId,
+        entities,
+      }),
+      room: Object.freeze({ ...room, readySeats }),
+    });
+  }
+
+  playerOffline(parsed: ParsedSeatPayload): void {
+    const event = parseSeatAction(parsed);
+    const previous = this.getState();
+    const room = requireInsideRoom(previous);
+    const playerid = requireOccupiedSeat(room, event.seat);
+    if (room.offlineSeats.includes(event.seat)) {
+      throw new RangeError('$.event.seat: player is already offline');
+    }
+    const player = previous.players.entities[playerid];
+    if (player === undefined) {
+      throw new RangeError('players.entities: occupied seat has no canonical player');
+    }
+    const entities = Object.freeze({
+      ...previous.players.entities,
+      [playerid]: Object.freeze({ ...player, onstate: 1 }),
+    });
+    const offlineSeats = Object.freeze([...room.offlineSeats, event.seat]);
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: Object.freeze({
+        selfPlayerId: previous.players.selfPlayerId,
+        entities,
+      }),
+      room: Object.freeze({ ...room, offlineSeats }),
+    });
+  }
+
+  playerOnline(parsed: ParsedOnlinePayload): void {
+    const event = parseSeatAction(parsed);
+    const input = requireRecord(parsed, '$.event');
+    const ip = requireString(input.ip, '$.event.ip');
+    if (requireString(event.raw.ip, '$.event.raw.ip') !== ip) {
+      throw new RangeError('$.event.raw.ip: expected the parsed ip');
+    }
+    const previous = this.getState();
+    const room = requireInsideRoom(previous);
+    const playerid = requireOccupiedSeat(room, event.seat);
+    if (!room.offlineSeats.includes(event.seat)) {
+      throw new RangeError('$.event.seat: player is already online');
+    }
+    const player = previous.players.entities[playerid];
+    if (player === undefined) {
+      throw new RangeError('players.entities: occupied seat has no canonical player');
+    }
+    const entities = Object.freeze({
+      ...previous.players.entities,
+      [playerid]: Object.freeze({ ...player, ip, onstate: 0 }),
+    });
+    const offlineSeats = Object.freeze(
+      room.offlineSeats.filter((seat) => seat !== event.seat),
+    );
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: Object.freeze({
+        selfPlayerId: previous.players.selfPlayerId,
+        entities,
+      }),
+      room: Object.freeze({ ...room, offlineSeats }),
+    });
+  }
+
+  playerExit(parsed: ParsedSeatPayload): void {
+    const event = parseSeatAction(parsed);
+    const previous = this.getState();
+    const room = requireInsideRoom(previous);
+    const playerid = requireOccupiedSeat(room, event.seat);
+    if (event.seat === room.selfSeat) {
+      throw new RangeError('$.event.seat: self exit must clear the room');
+    }
+
+    const entities: Record<number, PlatformPlayer> = {
+      ...previous.players.entities,
+    };
+    delete entities[playerid];
+    const seatPlayerIds = [...room.seatPlayerIds];
+    seatPlayerIds[event.seat] = null;
+    const readySeats = room.readySeats.filter((seat) => seat !== event.seat);
+    const offlineSeats = room.offlineSeats.filter((seat) => seat !== event.seat);
+
+    this.stateCell.value = Object.freeze({
+      app: previous.app,
+      players: Object.freeze({
+        selfPlayerId: previous.players.selfPlayerId,
+        entities: Object.freeze(entities),
+      }),
+      room: Object.freeze({
+        ...room,
+        seatPlayerIds: Object.freeze(seatPlayerIds),
+        readySeats: Object.freeze(readySeats),
+        offlineSeats: Object.freeze(offlineSeats),
+      }),
+    });
+  }
+}
diff --git a/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/platform-types.ts b/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/platform-types.ts
new file mode 100644
index 0000000..e711af7
--- /dev/null
+++ b/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/platform-types.ts
@@ -0,0 +1,49 @@
+import type { PlatformGameConnectionPhase } from '../../sdk/contracts/snapshots.ts';
+
+export type PlatformConnectionPhase =
+  | 'idle'
+  | 'connecting'
+  | PlatformGameConnectionPhase;
+
+export interface PlatformAppState {
+  readonly phase: PlatformConnectionPhase;
+}
+
+export interface PlatformPlayer {
+  readonly playerid: number;
+  readonly nickname: string;
+  readonly avatar: string;
+  readonly ip?: string;
+  readonly isprepare?: number;
+  readonly onstate?: number;
+}
+
+export interface PlayerDirectoryState {
+  readonly selfPlayerId: number | null;
+  readonly entities: Readonly<Record<number, PlatformPlayer>>;
+}
+
+export interface OutsideRoomState {
+  readonly kind: 'outside';
+}
+
+export interface InsideRoomState {
+  readonly kind: 'inside';
+  readonly roomcode: string;
+  readonly selfSeat: number;
+  readonly seatPlayerIds: readonly (number | null)[];
+  readonly readySeats: readonly number[];
+  readonly offlineSeats: readonly number[];
+  readonly roomtype: readonly unknown[];
+  readonly stage: number;
+  readonly needprepare: number;
+  readonly infinite: number;
+}
+
+export type RoomState = OutsideRoomState | InsideRoomState;
+
+export interface PlatformState {
+  readonly app: PlatformAppState;
+  readonly players: PlayerDirectoryState;
+  readonly room: RoomState;
+}
diff --git a/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/selectors.ts b/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/selectors.ts
new file mode 100644
index 0000000..1d8c90c
--- /dev/null
+++ b/cocoscreator_projects/YouleNexus/assets/framework/platform/stores/selectors.ts
@@ -0,0 +1,188 @@
+import type {
+  GameSeatSnapshot,
+  PlatformGameAppSnapshot,
+  PlatformGameConnectionPhase,
+  PlatformGameRoomSnapshot,
+  PlatformGameSelfSnapshot,
+  PlatformGameSnapshot,
+} from '../../sdk/contracts/snapshots.ts';
+import type {
+  InsideRoomState,
+  PlatformAppState,
+  PlatformPlayer,
+  PlatformState,
+  PlayerDirectoryState,
+} from './platform-types.ts';
+
+const roomPlayerCache = new WeakMap<
+  InsideRoomState,
+  WeakMap<PlayerDirectoryState, readonly (PlatformPlayer | null)[]>
+>();
+const connectionCache = new WeakMap<PlatformAppState, PlatformGameAppSnapshot>();
+const roomSnapshotCache = new WeakMap<InsideRoomState, PlatformGameRoomSnapshot>();
+const selfSnapshotCache = new WeakMap<
+  InsideRoomState,
+  WeakMap<PlayerDirectoryState, PlatformGameSelfSnapshot>
+>();
+const seatsSnapshotCache = new WeakMap<
+  InsideRoomState,
+  WeakMap<PlayerDirectoryState, readonly GameSeatSnapshot[]>
+>();
+const gameSnapshotCache = new WeakMap<
+  PlatformAppState,
+  WeakMap<PlayerDirectoryState, WeakMap<InsideRoomState, PlatformGameSnapshot>>
+>();
+
+export function selectSelfPlayer(state: PlatformState): PlatformPlayer | null {
+  const playerId = state.players.selfPlayerId;
+  if (playerId === null) return null;
+  const player = state.players.entities[playerId];
+  if (player === undefined) {
+    throw new RangeError('players.entities: missing authenticated player');
+  }
+  return player;
+}
+
+export function selectRoomPlayers(
+  state: PlatformState,
+): readonly (PlatformPlayer | null)[] {
+  if (state.room.kind !== 'inside') {
+    throw new Error('room: expected player to be inside a room');
+  }
+  let byPlayers = roomPlayerCache.get(state.room);
+  if (byPlayers === undefined) {
+    byPlayers = new WeakMap();
+    roomPlayerCache.set(state.room, byPlayers);
+  }
+  const cached = byPlayers.get(state.players);
+  if (cached !== undefined) return cached;
+
+  const result = state.room.seatPlayerIds.map((playerid, seat) => {
+    if (playerid === null) return null;
+    const player = state.players.entities[playerid];
+    if (player === undefined) {
+      throw new RangeError(`players.entities: missing player for occupied seat ${seat}`);
+    }
+    return player;
+  });
+  const frozen = Object.freeze(result);
+  byPlayers.set(state.players, frozen);
+  return frozen;
+}
+
+function selectConnectionPhase(state: PlatformState): PlatformGameConnectionPhase {
+  const phase = state.app.phase;
+  if (phase === 'idle' || phase === 'connecting') {
+    throw new Error(`app.phase: cannot expose game snapshot while ${phase}`);
+  }
+  return phase;
+}
+
+function selectConnectionSnapshot(state: PlatformState): PlatformGameAppSnapshot {
+  const cached = connectionCache.get(state.app);
+  if (cached !== undefined) return cached;
+  const snapshot = Object.freeze({ phase: selectConnectionPhase(state) });
+  connectionCache.set(state.app, snapshot);
+  return snapshot;
+}
+
+function selectSelfSnapshot(
+  state: PlatformState,
+  room: InsideRoomState,
+): PlatformGameSelfSnapshot {
+  let byPlayers = selfSnapshotCache.get(room);
+  if (byPlayers === undefined) {
+    byPlayers = new WeakMap();
+    selfSnapshotCache.set(room, byPlayers);
+  }
+  const cached = byPlayers.get(state.players);
+  if (cached !== undefined) return cached;
+  const self = selectSelfPlayer(state);
+  if (self === null) {
+    throw new Error('players.selfPlayerId: expected authenticated player');
+  }
+  if (room.seatPlayerIds[room.selfSeat] !== self.playerid) {
+    throw new RangeError('room.selfSeat: expected authenticated player seat');
+  }
+  const snapshot = Object.freeze({ playerId: self.playerid, seat: room.selfSeat });
+  byPlayers.set(state.players, snapshot);
+  return snapshot;
+}
+
+function selectRoomSnapshot(room: InsideRoomState): PlatformGameRoomSnapshot {
+  const cached = roomSnapshotCache.get(room);
+  if (cached !== undefined) return cached;
+  const snapshot = Object.freeze({
+    roomcode: room.roomcode,
+    roomtype: room.roomtype,
+    stage: room.stage,
+    needprepare: room.needprepare,
+    infinite: room.infinite,
+  });
+  roomSnapshotCache.set(room, snapshot);
+  return snapshot;
+}
+
+function selectSeatsSnapshot(
+  state: PlatformState,
+  room: InsideRoomState,
+): readonly GameSeatSnapshot[] {
+  let byPlayers = seatsSnapshotCache.get(room);
+  if (byPlayers === undefined) {
+    byPlayers = new WeakMap();
+    seatsSnapshotCache.set(room, byPlayers);
+  }
+  const cached = byPlayers.get(state.players);
+  if (cached !== undefined) return cached;
+
+  const seats: GameSeatSnapshot[] = [];
+  const roomPlayers = selectRoomPlayers(state);
+  for (let seat = 0; seat < roomPlayers.length; seat += 1) {
+    const player = roomPlayers[seat];
+    if (player === null) continue;
+    if (player.onstate === undefined) {
+      throw new TypeError(`players.entities[${player.playerid}].onstate: expected protocol number`);
+    }
+    if (player.isprepare === undefined) {
+      throw new TypeError(`players.entities[${player.playerid}].isprepare: expected protocol number`);
+    }
+    seats.push(Object.freeze({
+      seat,
+      playerId: player.playerid,
+      nickname: player.nickname,
+      avatar: player.avatar,
+      online: player.onstate !== 1,
+      ready: player.isprepare === 1,
+    }));
+  }
+  const snapshot = Object.freeze(seats);
+  byPlayers.set(state.players, snapshot);
+  return snapshot;
+}
+
+export function selectGameSnapshot(state: PlatformState): PlatformGameSnapshot {
+  if (state.room.kind !== 'inside') {
+    throw new Error('room: expected player to be inside a room');
+  }
+  let byPlayers = gameSnapshotCache.get(state.app);
+  if (byPlayers === undefined) {
+    byPlayers = new WeakMap();
+    gameSnapshotCache.set(state.app, byPlayers);
+  }
+  let byRoom = byPlayers.get(state.players);
+  if (byRoom === undefined) {
+    byRoom = new WeakMap();
+    byPlayers.set(state.players, byRoom);
+  }
+  const cached = byRoom.get(state.room);
+  if (cached !== undefined) return cached;
+
+  const snapshot = Object.freeze({
+    connection: selectConnectionSnapshot(state),
+    self: selectSelfSnapshot(state, state.room),
+    room: selectRoomSnapshot(state.room),
+    seats: selectSeatsSnapshot(state, state.room),
+  });
+  byRoom.set(state.room, snapshot);
+  return snapshot;
+}
diff --git a/cocoscreator_projects/framework-tests/platform/platform-store.test.ts b/cocoscreator_projects/framework-tests/platform/platform-store.test.ts
new file mode 100644
index 0000000..3f8f51e
--- /dev/null
+++ b/cocoscreator_projects/framework-tests/platform/platform-store.test.ts
@@ -0,0 +1,306 @@
+import { readFileSync } from 'node:fs';
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { PlatformStore } from '../../YouleNexus/assets/framework/platform/stores/platform-store.ts';
+import {
+  parseLoginResponse,
+  parseOtherExitRoomPayload,
+  parseOtherOfflinePayload,
+  parseOtherJoinRoomPayload,
+  parseOtherOnlinePayload,
+  parsePlayerPreparePayload,
+  parseSelfJoinRoomResponse,
+} from '../../YouleNexus/assets/framework/protocol/contracts/index.ts';
+
+function fixture(name: string): { data: Record<string, unknown> } {
+  return JSON.parse(readFileSync(new URL(`../fixtures/contracts/${name}`, import.meta.url), 'utf8'));
+}
+
+test('PlatformStore starts unauthenticated and outside a room', () => {
+  const state = new PlatformStore().getState();
+  assert.equal(state.players.selfPlayerId, null);
+  assert.deepEqual(state.room, { kind: 'outside' });
+});
+
+test('applyLoginSuccess commits the complete login once and notifies once', () => {
+  const store = new PlatformStore();
+  const parsedLogin = parseLoginResponse(fixture('player-login-success.json').data);
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.applyLoginSuccess(parsedLogin);
+
+  const state = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(state.app.phase, 'logged-in');
+  assert.equal(state.players.selfPlayerId, 430511);
+  assert.deepEqual(state.players.entities[430511], {
+    playerid: 430511,
+    nickname: '测试号',
+    avatar: 'http://a',
+    ip: '127.0.0.1',
+  });
+  assert.deepEqual(state.room, { kind: 'outside' });
+});
+
+test('room login stores one canonical player entity and recursively freezes roomtype', () => {
+  const data = fixture('player-login-room.json').data;
+  const parsedLogin = parseLoginResponse(data);
+  const store = new PlatformStore();
+
+  store.applyLoginSuccess(parsedLogin);
+
+  const state = store.getState();
+  assert.equal(state.players.selfPlayerId, 430511);
+  assert.deepEqual(Object.keys(state.players.entities), ['430511']);
+  assert.equal(state.players.entities[430511]?.nickname, '测试号');
+  assert.equal(state.room.kind, 'inside');
+  if (state.room.kind !== 'inside') return;
+  const room = state.room;
+  assert.deepEqual(room.seatPlayerIds, [null, 430511, null, null]);
+  assert.equal(state.players.entities[430511]?.isprepare, 1);
+  assert.equal(state.players.entities[430511]?.onstate, 1);
+  assert.equal(typeof state.players.entities[430511]?.isprepare, 'number');
+  assert.equal(typeof state.players.entities[430511]?.onstate, 'number');
+  assert.equal(room.roomtype, data.roomtype);
+  assert.equal(Object.isFrozen(room.roomtype), true);
+  assert.equal(Object.isFrozen(room.roomtype[5]), true);
+  assert.equal(Object.isFrozen((room.roomtype[5] as unknown[])[2]), true);
+  assert.equal('deskinfo' in state, false);
+  assert.equal('deskinfo' in state.room, false);
+  assert.throws(() => {
+    (room.roomtype[5] as unknown[])[0] = 99;
+  }, TypeError);
+});
+
+test('playerJoin atomically adds one canonical entity and its seat id', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+  const joined = parseOtherJoinRoomPayload({
+    seat: 2,
+    playerid: 77,
+    nickname: '对家',
+    avatar: 'http://b',
+    sex: 1,
+    ip: '127.0.0.2',
+    onstate: 0,
+    bean: 90,
+    isprepare: 0,
+  });
+
+  store.playerJoin(joined);
+
+  const state = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(state.room.kind, 'inside');
+  if (state.room.kind !== 'inside') return;
+  assert.deepEqual(state.room.seatPlayerIds, [null, 430511, 77, null]);
+  assert.deepEqual(state.players.entities[77], {
+    playerid: 77,
+    nickname: '对家',
+    avatar: 'http://b',
+    ip: '127.0.0.2',
+    isprepare: 0,
+    onstate: 0,
+  });
+  assert.equal(Object.isFrozen(state.players.entities[77]), true);
+});
+
+test('playerReady replaces the affected player and room subtrees without prior mutation', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  store.playerJoin(parseOtherJoinRoomPayload({
+    seat: 2, playerid: 77, nickname: '对家', avatar: 'http://b',
+    ip: '127.0.0.2', onstate: 0, isprepare: 0,
+  }));
+  const before = store.getState();
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.playerReady(parsePlayerPreparePayload({ seat: 2 }));
+
+  const after = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(after.app, before.app);
+  assert.notEqual(after.players, before.players);
+  assert.equal(after.players.entities[77]?.isprepare, 1);
+  assert.notEqual(after.room, before.room);
+  assert.equal(after.room.kind, 'inside');
+  assert.equal(before.room.kind, 'inside');
+  if (after.room.kind !== 'inside' || before.room.kind !== 'inside') return;
+  assert.deepEqual(before.room.readySeats, [1]);
+  assert.deepEqual(after.room.readySeats, [1, 2]);
+  assert.equal(Object.isFrozen(after.room.readySeats), true);
+});
+
+test('playerOffline records protocol and room status with one atomic commit', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  store.playerJoin(parseOtherJoinRoomPayload({
+    seat: 2, playerid: 77, nickname: '对家', avatar: 'http://b',
+    ip: '127.0.0.2', onstate: 0, isprepare: 0,
+  }));
+  const before = store.getState();
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.playerOffline(parseOtherOfflinePayload({ seat: 2 }));
+
+  const after = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(after.app, before.app);
+  assert.notEqual(after.players, before.players);
+  assert.equal(after.players.entities[77]?.onstate, 1);
+  assert.equal(after.room.kind, 'inside');
+  assert.equal(before.room.kind, 'inside');
+  if (after.room.kind !== 'inside' || before.room.kind !== 'inside') return;
+  assert.deepEqual(before.room.offlineSeats, [1]);
+  assert.deepEqual(after.room.offlineSeats, [1, 2]);
+});
+
+test('playerOnline updates the canonical player ip and removes the offline seat atomically', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  const before = store.getState();
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.playerOnline(parseOtherOnlinePayload({ seat: 1, ip: '127.0.0.9' }));
+
+  const after = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(after.app, before.app);
+  assert.notEqual(after.players, before.players);
+  assert.notEqual(after.room, before.room);
+  assert.equal(after.players.entities[430511]?.ip, '127.0.0.9');
+  assert.equal(before.players.entities[430511]?.ip, '127.0.0.1');
+  assert.equal(after.room.kind, 'inside');
+  if (after.room.kind !== 'inside') return;
+  assert.deepEqual(after.room.offlineSeats, []);
+});
+
+test('playerExit removes the seat entity and every seat-owned status in one commit', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  store.playerJoin(parseOtherJoinRoomPayload({
+    seat: 2, playerid: 77, nickname: '对家', avatar: 'http://b',
+    ip: '127.0.0.2', onstate: 1, isprepare: 1,
+  }));
+  const before = store.getState();
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.playerExit(parseOtherExitRoomPayload({ seat: 2 }));
+
+  const after = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(after.app, before.app);
+  assert.equal(after.players.selfPlayerId, 430511);
+  assert.equal(after.players.entities[430511], before.players.entities[430511]);
+  assert.equal(after.players.entities[77], undefined);
+  assert.equal(after.room.kind, 'inside');
+  if (after.room.kind !== 'inside') return;
+  assert.deepEqual(after.room.seatPlayerIds, [null, 430511, null, null]);
+  assert.deepEqual(after.room.readySeats, [1]);
+  assert.deepEqual(after.room.offlineSeats, [1]);
+});
+
+test('replaceRoom atomically replaces the complete room from a parsed DTO', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-success.json').data));
+  const parsedRoom = parseSelfJoinRoomResponse(fixture('self-join-room.json').data);
+  const before = store.getState();
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.replaceRoom(parsedRoom);
+
+  const after = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(after.app, before.app);
+  assert.equal(after.room.kind, 'inside');
+  if (after.room.kind !== 'inside') return;
+  assert.equal(after.room.roomcode, '100001');
+  assert.equal(after.room.selfSeat, 1);
+  assert.equal(after.room.stage, 1);
+  assert.equal(after.room.needprepare, 1);
+  assert.equal(after.room.infinite, 0);
+  assert.deepEqual(after.room.seatPlayerIds, [null, 430511, null, null]);
+  assert.equal(after.room.roomtype, parsedRoom.room?.roomtype);
+  assert.equal(after.players.entities[430511]?.ip, '127.0.0.1');
+});
+
+test('clearRoom leaves no fabricated room fields and retains only the self entity', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  store.playerJoin(parseOtherJoinRoomPayload({
+    seat: 2, playerid: 77, nickname: '对家', avatar: 'http://b',
+    ip: '127.0.0.2', onstate: 0, isprepare: 0,
+  }));
+  const before = store.getState();
+  const self = before.players.entities[430511];
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  store.clearRoom();
+
+  const after = store.getState();
+  assert.equal(notifications, 1);
+  assert.equal(after.app, before.app);
+  assert.deepEqual(after.room, { kind: 'outside' });
+  assert.deepEqual(Object.keys(after.room), ['kind']);
+  assert.deepEqual(Object.keys(after.players.entities), ['430511']);
+  assert.equal(after.players.entities[430511], self);
+});
+
+test('failed actions keep the exact root, notify nobody, and do not mutate inputs', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  const before = store.getState();
+  let notifications = 0;
+  store.subscribe(() => { notifications += 1; });
+
+  const tampered = parseSelfJoinRoomResponse(fixture('self-join-room.json').data);
+  (tampered.room as { roomcode: string }).roomcode = 'tampered';
+  assert.throws(() => store.replaceRoom(tampered), /roomcode/);
+  assert.equal(store.getState(), before);
+  assert.equal(notifications, 0);
+
+  assert.throws(
+    () => store.playerReady(parsePlayerPreparePayload({ seat: 99 })),
+    /seat/,
+  );
+  assert.equal(store.getState(), before);
+  assert.equal(notifications, 0);
+
+  assert.throws(
+    () => store.playerJoin(parseOtherJoinRoomPayload({
+      seat: 2, playerid: 430511, nickname: '重复', avatar: 'http://duplicate',
+      ip: '127.0.0.3', onstate: 0, isprepare: 0,
+    })),
+    /duplicate player seat/,
+  );
+  assert.equal(store.getState(), before);
+  assert.equal(notifications, 0);
+
+  const duplicateData = fixture('self-join-room.json').data;
+  const duplicatePlayers = duplicateData.players as Array<Record<string, unknown> | null>;
+  duplicatePlayers[2] = { ...duplicatePlayers[1] as Record<string, unknown> };
+  const mutableRoomtype = duplicateData.roomtype as unknown[];
+  const duplicateRoom = parseSelfJoinRoomResponse(duplicateData);
+  assert.throws(() => store.replaceRoom(duplicateRoom), /duplicate player seat/);
+  assert.equal(Object.isFrozen(mutableRoomtype), false);
+  assert.equal(store.getState(), before);
+  assert.equal(notifications, 0);
+
+  assert.throws(() => {
+    (before.players.entities[430511] as { nickname: string }).nickname = '篡改';
+  }, TypeError);
+  assert.throws(() => {
+    (before.room as { kind: string }).kind = 'outside';
+  }, TypeError);
+  assert.equal(store.getState(), before);
+  assert.equal(notifications, 0);
+});
diff --git a/cocoscreator_projects/framework-tests/platform/selectors.test.ts b/cocoscreator_projects/framework-tests/platform/selectors.test.ts
new file mode 100644
index 0000000..45ee659
--- /dev/null
+++ b/cocoscreator_projects/framework-tests/platform/selectors.test.ts
@@ -0,0 +1,132 @@
+import { readFileSync } from 'node:fs';
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  selectGameSnapshot,
+  selectRoomPlayers,
+  selectSelfPlayer,
+} from '../../YouleNexus/assets/framework/platform/stores/selectors.ts';
+import { PlatformStore } from '../../YouleNexus/assets/framework/platform/stores/platform-store.ts';
+import type { PlatformState } from '../../YouleNexus/assets/framework/platform/stores/platform-types.ts';
+import { parseLoginResponse } from '../../YouleNexus/assets/framework/protocol/contracts/index.ts';
+
+function fixture(name: string): { data: Record<string, unknown> } {
+  return JSON.parse(readFileSync(new URL(`../fixtures/contracts/${name}`, import.meta.url), 'utf8'));
+}
+
+test('selectSelfPlayer returns null for an unauthenticated state', () => {
+  const state = {
+    app: { phase: 'idle' },
+    players: { selfPlayerId: null, entities: {} },
+    room: { kind: 'outside' },
+  } as PlatformState;
+  assert.equal(selectSelfPlayer(state), null);
+});
+
+test('selectRoomPlayers memoizes a frozen positional projection of canonical entities', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  const state = store.getState();
+
+  const first = selectRoomPlayers(state);
+  const second = selectRoomPlayers(state);
+
+  assert.equal(first, second);
+  assert.equal(Object.isFrozen(first), true);
+  assert.deepEqual(
+    first.map((player) => player === null ? null : player.playerid),
+    [null, 430511, null, null],
+  );
+  assert.equal(first[1], selectSelfPlayer(state));
+  assert.throws(() => {
+    (first as unknown[])[1] = null;
+  }, TypeError);
+});
+
+test('selectGameSnapshot returns only recursively frozen SDK-owned DTOs', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  const state = store.getState();
+  assert.equal(state.room.kind, 'inside');
+  if (state.room.kind !== 'inside') return;
+
+  const snapshot = selectGameSnapshot(state);
+
+  assert.deepEqual(snapshot, {
+    connection: { phase: 'logged-in' },
+    self: { playerId: 430511, seat: 1 },
+    room: {
+      roomcode: '100001',
+      roomtype: state.room.roomtype,
+      stage: 1,
+      needprepare: 1,
+      infinite: 0,
+    },
+    seats: [{
+      seat: 1,
+      playerId: 430511,
+      nickname: '测试号',
+      avatar: 'http://a',
+      online: false,
+      ready: true,
+    }],
+  });
+  assert.equal(Object.isFrozen(snapshot), true);
+  assert.equal(Object.isFrozen(snapshot.connection), true);
+  assert.equal(Object.isFrozen(snapshot.self), true);
+  assert.equal(Object.isFrozen(snapshot.room), true);
+  assert.equal(Object.isFrozen(snapshot.seats), true);
+  assert.equal(Object.isFrozen(snapshot.seats[0]), true);
+  assert.equal(snapshot.room.roomtype, state.room.roomtype);
+  assert.deepEqual(Object.keys(snapshot).sort(), ['connection', 'room', 'seats', 'self']);
+});
+
+test('selectGameSnapshot memoizes each SDK branch by its immutable source subtrees', () => {
+  const store = new PlatformStore();
+  store.applyLoginSuccess(parseLoginResponse(fixture('player-login-room.json').data));
+  const base = store.getState();
+  assert.equal(base.room.kind, 'inside');
+  if (base.room.kind !== 'inside') return;
+
+  const first = selectGameSnapshot(base);
+  const repeated = selectGameSnapshot(base);
+  assert.equal(repeated, first);
+  assert.equal(repeated.connection, first.connection);
+  assert.equal(repeated.self, first.self);
+  assert.equal(repeated.room, first.room);
+  assert.equal(repeated.seats, first.seats);
+
+  const appChanged: PlatformState = Object.freeze({
+    ...base,
+    app: Object.freeze({ phase: 'reconnecting' }),
+  });
+  const afterApp = selectGameSnapshot(appChanged);
+  assert.notEqual(afterApp, first);
+  assert.notEqual(afterApp.connection, first.connection);
+  assert.equal(afterApp.self, first.self);
+  assert.equal(afterApp.room, first.room);
+  assert.equal(afterApp.seats, first.seats);
+
+  const playersChanged: PlatformState = Object.freeze({
+    ...base,
+    players: Object.freeze({
+      selfPlayerId: base.players.selfPlayerId,
+      entities: Object.freeze({ ...base.players.entities }),
+    }),
+  });
+  const afterPlayers = selectGameSnapshot(playersChanged);
+  assert.equal(afterPlayers.connection, first.connection);
+  assert.notEqual(afterPlayers.self, first.self);
+  assert.equal(afterPlayers.room, first.room);
+  assert.notEqual(afterPlayers.seats, first.seats);
+
+  const roomChanged: PlatformState = Object.freeze({
+    ...base,
+    room: Object.freeze({ ...base.room, stage: 0 }),
+  });
+  const afterRoom = selectGameSnapshot(roomChanged);
+  assert.equal(afterRoom.connection, first.connection);
+  assert.notEqual(afterRoom.self, first.self);
+  assert.notEqual(afterRoom.room, first.room);
+  assert.notEqual(afterRoom.seats, first.seats);
+});