引入 AGC 随包资源的单一声明与生成门禁

- 新增 build_support/package-layout.json：Codex 三元表与组件白名单、上游候选路径、第三方声明来源、插件随包子目录与跳过规则、平台与 feature 门槛的唯一人工声明
- 新增 scripts/check-package-layout.mjs：由声明生成 build_support/package-layout.generated.rs，并校验目标唯一、可执行组件属于白名单、每个目标恰有一条第三方声明来源、codex.version 与应用锁定的 @openai/codex 一致
- 新增 build_support/package_layout.rs：声明类型、插件与平台门槛判定、逐块 sha256、随包 Codex 目录只读校验及其单测
- codex_bundle.rs 的布局与版本常量改由声明提供，公开接口与取值不变；src/main.rs 在测试期引入该模块以复用既有单测
- package.json 新增 bundled-resources:check/sync 并接进 typecheck 链，根 package.json 提供 agc:* 别名

package.json

@@ -168,6 +168,10 @@
     "agc:build": "npm --prefix apps/ai-game-creator-shell run build --",
     "agc:skill-pack:check": "npm --prefix apps/ai-game-creator-shell run skill-pack:check",
     "agc:skill-pack:sync": "npm --prefix apps/ai-game-creator-shell run skill-pack:sync",
+    "agc:bundled-resources:check": "npm --prefix apps/ai-game-creator-shell run bundled-resources:check",
+    "agc:bundled-resources:sync": "npm --prefix apps/ai-game-creator-shell run bundled-resources:sync",
+    "agc:bundled-resources:prepare": "npm --prefix apps/ai-game-creator-shell run bundled-resources:prepare",
+    "agc:bundled-resources:test": "npm --prefix apps/ai-game-creator-shell run bundled-resources:test",
     "agc:plugins:test": "node --test plugins/agc-cocos-editor/src/entry.test.mjs plugins/agc-unity-editor/src/entry.test.mjs plugins/agc-godot-editor/src/entry.test.mjs",
     "agc:plugins:native-test": "cargo test --manifest-path plugins/agc-cocos-editor/native/cocos-editor-bridge/Cargo.toml && cargo test --locked --manifest-path plugins/agc-unity-editor/native/unity-editor-bridge/Cargo.toml && cargo test --locked --manifest-path plugins/agc-godot-editor/native/godot-editor-bridge/Cargo.toml",
     "agc:plugins:check": "npm run agc:plugins:test && npm run agc:plugins:native-test",