feat(meta): 主菜单解锁面板（花碎片解锁法术）

scenes/ui/main_menu.gd

@@ -5,6 +5,8 @@ var _settings_layer: CanvasLayer = null
 var _settings_root: Control = null
 var _leaderboard_layer: CanvasLayer = null
 var _ftue_layer: CanvasLayer = null
+var _unlock_layer: CanvasLayer = null
+var _unlock_root: Control = null
 var _continue_btn: Button = null
 var _quit_confirm: bool = false
 
@@ -15,6 +17,7 @@ func _ready() -> void:
 	_build_settings_panel()
 	_build_leaderboard_panel()
 	_build_ftue_panel()
+	_build_unlock_panel()
 
 func _build_bg() -> void:
 	# 深色渐变背景
@@ -49,6 +52,7 @@ func _build_menu() -> void:
 		["MENU_NEW_GAME", _on_new_game],
 		["MENU_CONTINUE", _on_continue],
 		["MENU_LEADERBOARD", _on_leaderboard],
+		["MENU_UNLOCK", _on_unlock],
 		["MENU_SETTINGS", _on_settings],
 		["MENU_QUIT", _on_quit],
 	]
@@ -121,11 +125,13 @@ func _on_lang() -> void:
 		c.queue_free()
 	_settings_layer = null
 	_leaderboard_layer = null
+	_unlock_layer = null
 	_settings_root = null
 	_build_bg()
 	_build_menu()
 	_build_settings_panel()
 	_build_leaderboard_panel()
+	_build_unlock_panel()
 
 func _on_quit() -> void:
 	if not _quit_confirm:
@@ -154,6 +160,8 @@ func _input(event: InputEvent) -> void:
 			_settings_layer.visible = false
 		elif _leaderboard_layer and _leaderboard_layer.visible:
 			_leaderboard_layer.visible = false
+		elif _unlock_layer and _unlock_layer.visible:
+			_unlock_layer.visible = false
 
 # ── 设置面板 ─────────────────────────────────────────────────
 func _build_settings_panel() -> void:
@@ -351,3 +359,77 @@ func _on_ftue_pick(difficulty_idx: int) -> void:
 	AudioManager.play("buy")
 	_ftue_layer.visible = false
 	SceneManager.start_new_game()
+
+# ── 解锁面板 ─────────────────────────────────────────────────
+func _on_unlock() -> void:
+	_unlock_layer.visible = true
+	_rebuild_unlock()
+
+func _build_unlock_panel() -> void:
+	_unlock_layer = CanvasLayer.new()
+	_unlock_layer.layer = 10
+	_unlock_layer.visible = false
+	add_child(_unlock_layer)
+	var bg := ColorRect.new()
+	bg.color = Color(0.0, 0.0, 0.0, 0.72)
+	bg.set_anchors_and_offsets_preset(Control.PRESET_FULL_RECT)
+	_unlock_layer.add_child(bg)
+	_unlock_root = Control.new()
+	_unlock_layer.add_child(_unlock_root)
+
+func _rebuild_unlock() -> void:
+	for c in _unlock_root.get_children():
+		c.queue_free()
+	var panel := ColorRect.new()
+	panel.color = Color(0.06, 0.06, 0.14, 0.98)
+	panel.size = Vector2(560, 470)
+	panel.position = Vector2(300, 90)
+	_unlock_root.add_child(panel)
+	var title := Label.new()
+	title.text = tr("META_TITLE")
+	title.position = Vector2(324, 106)
+	title.add_theme_font_size_override("font_size", 28)
+	title.modulate = Color.GOLD
+	_unlock_root.add_child(title)
+	var aether_lbl := Label.new()
+	aether_lbl.text = tr("META_AETHER") % MetaProgress.aether
+	aether_lbl.position = Vector2(324, 148)
+	aether_lbl.add_theme_font_size_override("font_size", 18)
+	aether_lbl.modulate = Color(0.6, 0.85, 1.0)
+	_unlock_root.add_child(aether_lbl)
+	var y: float = 188.0
+	for id in SpellRegistry.get_all_ids():
+		var s: SpellNode = SpellRegistry.get_spell(id)
+		if s == null:
+			continue
+		var cost: int = int(s.meta.get("unlock_cost", 0))
+		if cost <= 0:
+			continue
+		var name_lbl := Label.new()
+		name_lbl.text = s.display_name
+		name_lbl.position = Vector2(324, y + 4)
+		name_lbl.add_theme_font_size_override("font_size", 16)
+		_unlock_root.add_child(name_lbl)
+		var btn := Button.new()
+		btn.position = Vector2(560, y)
+		btn.size = Vector2(230, 32)
+		if MetaProgress.is_unlocked(id):
+			btn.text = tr("META_UNLOCKED")
+			btn.disabled = true
+		else:
+			btn.text = tr("META_UNLOCK_BTN") % cost
+			btn.disabled = MetaProgress.aether < cost
+			var sid := id
+			var scost := cost
+			btn.connect("pressed", func():
+				if MetaProgress.unlock(sid, scost):
+					AudioManager.play("buy")
+					_rebuild_unlock())
+		_unlock_root.add_child(btn)
+		y += 40.0
+	var close := Button.new()
+	close.text = tr("META_CLOSE")
+	close.position = Vector2(700, 508)
+	close.size = Vector2(120, 36)
+	close.connect("pressed", func(): _unlock_layer.visible = false)
+	_unlock_root.add_child(close)