feat: Extract BMGD module and implement workflow vendoring

This commit extracts game development functionality from BMM into a standalone
BMGD (BMad Game Development) module and implements workflow vendoring to enable
module independence.

BMGD Module Creation:
- Moved agents: game-designer, game-dev, game-architect from BMM to BMGD
- Moved team config: team-gamedev
- Created new Game Dev Scrum Master agent using workflow vendoring pattern
- Reorganized workflows into industry-standard game dev phases:
  * Phase 1 (Preproduction): brainstorm-game, game-brief
  * Phase 2 (Design): gdd, narrative
  * Phase 3 (Technical): game-architecture
  * Phase 4 (Production): vendored from BMM workflows
- Updated all module metadata and config_source references

Workflow Vendoring Feature:
- Enables modules to copy workflows from other modules during installation
- Build-time process that updates config_source in vendored workflows
- New agent YAML attribute: workflow-install (build-time metadata)
- Final compiled agents use workflow-install value for workflow attribute
- Implementation in module manager: vendorCrossModuleWorkflows()
- Allows standalone module installation without forced dependencies

Technical Changes:
- tools/cli/lib/yaml-xml-builder.js: Use workflow-install for workflow attribute
- tools/cli/installers/lib/modules/manager.js: Add vendoring functions
- tools/schema/agent.js: Add workflow-install to menu item schema
- Updated 3 documentation files with workflow vendoring details

BMM Workflow Updates:
- workflow-status/init: Added game detection checkpoint
- workflow-status/paths/game-design.yaml: Redirect to BMGD module
- prd/instructions.md: Route game projects to BMGD
- research/instructions-market.md: Reference BMGD for game development

Documentation:
- Created comprehensive BMGD module README
- Added workflow vendoring documentation
- Updated BMB agent creation and module creation guides

src/modules/bmm/workflows/workflow-status/init/instructions.md

@@ -317,6 +317,56 @@ Your choice [1/2/3]:</ask>
 - Default to "software" if not clearly a game
   </action>
 
+<check if="project_type == game">
+  <output>
+  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+🎮 **GAME DEVELOPMENT DETECTED**
+
+Game development workflows are now part of the **BMad Game Development (BMGD)** module.
+
+The BMM module is designed for software development. For game development, you'll need
+the BMGD module which provides specialized game development workflows and agents.
+
+**Would you like to:**
+a) Install BMGD module now (recommended for game projects)
+b) Continue with BMM workflows (for software projects only)
+
+━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+</output>
+
+<ask>Your choice [a/b]:</ask>
+
+  <check if="choice == a">
+    <output>
+    Please run the following command to install the BMGD module:
+
+    ```bash
+    bmad install bmgd
+    ```
+
+    After installation, you can start your game development workflow with the Game Designer agent.
+
+    This workflow-init will now exit. Re-run it after installing BMGD.
+    </output>
+    <action>Exit workflow with success status</action>
+
+  </check>
+
+  <check if="choice == b">
+    <output>
+    ⚠️ **Warning:** BMM workflows are optimized for software development, not game development.
+
+    You may encounter mismatched terminology and workflows. Consider installing BMGD for
+    a better game development experience.
+
+    Continuing with software development workflows...
+    </output>
+    <action>Set project_type = "software" (override game detection)</action>
+
+  </check>
+</check>
+
 <template-output>user_description</template-output>
 <template-output>field_type</template-output>
 <template-output>project_type</template-output>

src/modules/bmm/workflows/workflow-status/paths/game-design.yaml

@@ -1,75 +1,52 @@
-# Game Design - All Levels
-# Game development follows a different path than software
+# Game Development - Use BMGD Module
+# Game development workflows have been moved to the BMad Game Development module
 
 project_type: "game"
 level: "all"
 field_type: "any"
-description: "Game development workflow - applies to all complexity levels"
+description: "⚠️ Game development requires the BMGD module"
 
+error_message: |
+  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+  🎮 **GAME DEVELOPMENT DETECTED**
+
+  Game development workflows are now part of the **BMad Game Development (BMGD)** module,
+  which provides specialized workflows and agents for game creation.
+
+  **To proceed with game development:**
+
+  1. Install the BMGD module:
+     ```bash
+     bmad install bmgd
+     ```
+
+  2. The BMGD module includes:
+     - Game Designer, Game Developer, Game Architect agents
+     - Game Dev Scrum Master for sprint coordination
+     - Industry-standard game dev workflows:
+       • Phase 1 (Preproduction): brainstorm-game, game-brief
+       • Phase 2 (Design): GDD, narrative design
+       • Phase 3 (Technical): game architecture
+       • Phase 4 (Production): sprint planning, story management
+
+  3. After installation, load the Game Designer or Game Dev Scrum Master agent
+     to begin your game development workflow
+
+  **Why a separate module?**
+  - Game development follows different phases than software development
+  - Specialized agents understand game-specific terminology and patterns
+  - Workflows configured for game development needs (playtesting, balancing, etc.)
+  - Can be used standalone or alongside BMM for complete coverage
+
+  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
+
+# Placeholder phases - this file should not be used for actual workflow tracking
+# Users should install BMGD module instead
 phases:
   - phase: 1
-    name: "Analysis"
-    optional: true
+    name: "ERROR - Install BMGD Module"
     workflows:
-      - id: "brainstorm-game"
-        optional: true
-        agent: "game-designer"
-        command: "brainstorm-game"
-      - id: "research"
-        optional: true
-        agent: "analyst"
-        command: "research"
-        note: "Market research, competitive analysis"
-      - id: "game-brief"
-        recommended: true
-        agent: "game-designer"
-        command: "game-brief"
-        output: "Game concept and vision document"
-
-  - phase: 2
-    name: "Planning"
-    required: true
-    workflows:
-      - id: "gdd"
+      - id: "install-bmgd"
         required: true
-        agent: "pm"
-        command: "gdd"
-        output: "Game Design Document with features and mechanics"
-      - id: "tech-spec"
-        conditional: "if_level_0_1"
-        agent: "architect"
-        command: "tech-spec"
-        note: "For simpler games, jump to implementation"
-
-  - phase: 3
-    name: "Solutioning"
-    conditional: "if_level_3_4"
-    workflows:
-      - id: "create-architecture"
-        required: true
-        agent: "architect"
-        command: "create-architecture"
-        note: "Engine architecture, networking, systems"
-      - id: "validate-architecture"
-        optional: true
-        agent: "architect"
-        command: "validate-architecture"
-      - id: "solutioning-gate-check"
-        required: true
-        agent: "architect"
-        command: "solutioning-gate-check"
-
-  - phase: 4
-    name: "Implementation"
-    required: true
-    workflows:
-      - id: "sprint-planning"
-        required: true
-        agent: "sm"
-        command: "sprint-planning"
-        note: "Creates sprint plan with all stories - subsequent work tracked in sprint plan output, not workflow-status"
-
-special_considerations:
-  - "Iterative playtesting throughout development"
-  - "Art and audio pipelines run parallel to code"
-  - "Balance and tuning as ongoing process"
+        note: "Run: bmad install bmgd"