feat: Create and refine WeChat Mini-Game Expansion Pack

This commit introduces a new expansion pack for WeChat Mini-Game
development and includes significant refinements based on user feedback to
ensure correctness and consistency with the project's architecture.

The new `bmad-wechat-mini-game-dev` expansion pack includes:
- A `config.yaml` for pack metadata.
- Specialized agents: `@wechat-game-designer` and `@wechat-game-dev`.
- A central `data/development-guidelines.md` for standards.
- A `checklists/game-story-dod-checklist.md` for quality control.
- A YAML-based GDD template and a page scaffolding task.
- An `agent-teams/wechat-mini-game-team.yaml` for web UI support.
- A comprehensive `README.md`.

This work also includes the reversion of a previous, incorrect commit
that modified `bmad-core` files. Those changes have been reverted, and
the expansion pack is now correctly implemented to be fully
self-contained.

expansion-packs/bmad-wechat-mini-game-dev/README.md

@@ -38,6 +38,10 @@ This pack is designed to help you plan your game's structure, mechanics, and int
 
 *   **`checklists/game-story-dod-checklist.md`**: A "Definition of Done" checklist to ensure every story is completed to a consistent quality standard.
 
+### Web UI Support
+
+*   **`agent-teams/wechat-mini-game-team.yaml`**: Defines the agent team for use in web-based AI platforms. Use the `web-builder.js` tool to bundle this team for upload to a Custom GPT or other web UI.
+
 ---
 
 ## Quick-Start Workflow

expansion-packs/bmad-wechat-mini-game-dev/agent-teams/wechat-mini-game-team.yaml

@@ -0,0 +1,6 @@
+# <!-- Powered by BMAD™ Core -->
+name: WeChat Mini Game Dev Team
+description: A specialized team for planning and developing WeChat Mini Games.
+agents:
+  - wechat-game-designer
+  - wechat-game-dev