fix(sdk): enforce runtime dependency boundary

cocoscreator_projects/scripts/lib/import-boundaries.mjs

@@ -221,6 +221,7 @@ function findViolation(context) {
   const filePath = displayPath(file);
   const resolvedPath = resolved ? displayPath(resolved) : specifier;
   const isContract = CONTRACTS_PATH.test(filePath);
+  const isSdk = SDK_ALLOWED.test(filePath);
   const isGame = isInside(file, gamesDir);
   const isFramework = isInside(file, frameworkDir);
 
@@ -232,6 +233,14 @@ function findViolation(context) {
     return violation(filePath, specifier, `sdk/contracts may import only sibling contracts; sdk path resolved to ${resolvedPath}`);
   }
 
+  if (isSdk
+    && !isSdkMigrationBarrel(filePath, frameworkDir)
+    && resolved
+    && isInside(resolved, frameworkDir)
+    && !SDK_ALLOWED.test(resolvedPath)) {
+    return violation(filePath, specifier, `sdk cannot import framework implementation ${resolvedPath}`);
+  }
+
   if (isGame && resolved && isFrameworkReference(resolved, frameworkDir) && !SDK_ALLOWED.test(resolvedPath)) {
     return violation(filePath, specifier, `game code may import only framework/sdk; game import resolved to ${resolvedPath}`);
   }
@@ -264,6 +273,10 @@ function isLegacyRuntimeImporter(filePath, frameworkDir) {
   return filePath === `${normalizedFrameworkDir}/sdk/index.ts` || LEGACY_RUNTIME.test(filePath);
 }
 
+function isSdkMigrationBarrel(filePath, frameworkDir) {
+  return filePath === `${displayPath(frameworkDir)}/sdk/index.ts`;
+}
+
 /**
  * ActiveGame is the retained compatibility owner of IGameModule until Task 11
  * removes both it and the migration-only declarations from sdk/index.ts.