feat: Comprehensively optimize WeChat Mini-Game expansion pack

This commit represents a complete and comprehensive optimization of the `bmad-wechat-mini-game-dev` expansion pack, based on a series of detailed user requests. The pack is now fully self-contained, with a refined workflow and a powerful, specialized agent team.

Key Changes:

- **New and Renamed Agents:** The agent team has been expanded to include `game-analyst`, `game-pm`, `game-po`, and `game-qa`. `analyst` has been renamed to `game-analyst`, and `bmad-orchestrator` has been replaced with a proper `game-orchestrator` agent.

- **Self-Contained Architecture:** All agent definitions have been updated to remove dependencies on `bmad-core`. Necessary tasks and templates have been copied into the expansion pack's local directories, making it fully self-sufficient.

- **Refined Workflows:** The `game-dev-greenfield.yaml` and `game-prototype.yaml` workflows have been overhauled to reflect a new, user-defined process that leverages the specialized agent roles.

- **Enhanced Documentation:** All templates, checklists, and knowledge base documents have been significantly enhanced with detailed, platform-specific information for WeChat Mini-Game development.

- **Upgraded QA Agent:** The `game-qa` agent has been upgraded to a full Test Architect, with a comprehensive suite of QA tasks available locally.

- **Simplified Template Outputs:** The output filenames for all document templates have been simplified for better usability.

expansion-packs/bmad-wechat-mini-game-dev/templates/game-story-tmpl.yaml

@@ -5,7 +5,7 @@ template:
   version: 1.0
   output:
     format: markdown
-    filename: "stories/{{epic_name}}/{{story_id}}-{{story_name}}.md"
+    filename: "docs/stories/{{story_id}}-{{story_name}}.md"
     title: "Story: {{story_title}}"
 
 workflow: