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/bmgd/workflows/3-technical/game-architecture/architecture-template.md

@@ -0,0 +1,103 @@
+# Architecture
+
+## Executive Summary
+
+{{executive_summary}}
+
+{{project_initialization_section}}
+
+## Decision Summary
+
+| Category | Decision | Version | Affects Epics | Rationale |
+| -------- | -------- | ------- | ------------- | --------- |
+
+{{decision_table_rows}}
+
+## Project Structure
+
+```
+{{project_root}}/
+{{source_tree}}
+```
+
+## Epic to Architecture Mapping
+
+{{epic_mapping_table}}
+
+## Technology Stack Details
+
+### Core Technologies
+
+{{core_stack_details}}
+
+### Integration Points
+
+{{integration_details}}
+
+{{novel_pattern_designs_section}}
+
+## Implementation Patterns
+
+These patterns ensure consistent implementation across all AI agents:
+
+{{implementation_patterns}}
+
+## Consistency Rules
+
+### Naming Conventions
+
+{{naming_conventions}}
+
+### Code Organization
+
+{{code_organization_patterns}}
+
+### Error Handling
+
+{{error_handling_approach}}
+
+### Logging Strategy
+
+{{logging_approach}}
+
+## Data Architecture
+
+{{data_models_and_relationships}}
+
+## API Contracts
+
+{{api_specifications}}
+
+## Security Architecture
+
+{{security_approach}}
+
+## Performance Considerations
+
+{{performance_strategies}}
+
+## Deployment Architecture
+
+{{deployment_approach}}
+
+## Development Environment
+
+### Prerequisites
+
+{{development_prerequisites}}
+
+### Setup Commands
+
+```bash
+{{setup_commands}}
+```
+
+## Architecture Decision Records (ADRs)
+
+{{key_architecture_decisions}}
+
+---
+
+_Generated by BMAD Decision Architecture Workflow v1.0_
+_Date: {{date}}_
+_For: {{user_name}}_