feat: add custom agents and quick-flow workflows, remove tech-spec track

Major Changes:
- Add sample custom agents demonstrating installable agent system
  - commit-poet: Generates semantic commit messages (BMAD Method repo sample)
  - toolsmith: Development tooling expert with knowledge base covering bundlers, deployment, docs, installers, modules, and tests (BMAD Method repo sample)
  - Both agents demonstrate custom agent architecture and are installable to projects via BMAD installer system
  - Include comprehensive installation guides and sidecar knowledge bases

- Add bmad-quick-flow methodology for rapid development
  - create-tech-spec: Direct technical specification workflow
  - quick-dev: Flexible execution workflow supporting both tech-spec-driven and direct instruction development
  - quick-flow-solo-dev (Barry): 1 man show agent specialized in bmad-quick-flow methodology
  - Comprehensive documentation for quick-flow approach and solo development

- Remove deprecated tech-spec workflow track
  - Delete entire tech-spec workflow directory and templates
  - Remove quick-spec-flow.md documentation (replaced by quick-flow docs)
  - Clean up unused epic and story templates

- Fix custom agent installation across IDE installers
  - Repair antigravity and multiple IDE installers to properly support custom agents
  - Enable custom agent installation via quick installer, agent installer, regular installer, and special agent installer
  - All installation methods now accessible via npx with full documentation

Infrastructure:
- Update BMM module configurations and team setups
- Modify workflow status paths to support quick-flow integration
- Reorganize documentation with new agent and workflow guides
- Add custom/ directory for user customizations
- Update platform codes and installer configurations

src/modules/bmm/_module-installer/install-config.yaml

@@ -40,7 +40,6 @@ sprint_artifacts:
   default: "{output_folder}/sprint-artifacts"
   result: "{project-root}/{value}"
 
-# TEA Agent Configuration
 tea_use_mcp_enhancements:
   prompt: "Enable Test Architect Playwright MCP capabilities (healing, exploratory, verification)? You have to setup your MCPs yourself; refer to test-architecture.md for hints."
   default: false
@@ -53,16 +52,3 @@ tea_use_playwright_utils:
     - "You must install packages yourself, or use test architect's *framework command."
   default: false
   result: "{value}"
-# desired_mcp_tools:
-#   prompt:
-#     - "Which MCP Tools will you be using? (Select all that apply)"
-#     - "Note: You will need to install these separately. Bindings will come post ALPHA along with other choices."
-#   result: "{value}"
-#   multi-select:
-#     - "Chrome Official MCP"
-#     - "Playwright"
-#     - "Context 7"
-#     - "Tavily"
-#     - "Perplexity"
-#     - "Jira"
-#     - "Trello"