feat: reorganize capabilities directory structure for better separation

- Move issue-facade submodule from root to capabilities/ directory
- Update .gitmodules to reflect new submodule path: capabilities/issue-facade
- Update all documentation references to new capability paths
- Update agent definitions with new issue-facade location
- Establish logical organization: capabilities/ for all external dependencies
- Maintain wiki/ at root as project documentation, not reusable capability

Improves separation between:
- Project infrastructure (wiki/ at root)
- Reusable capabilities (capabilities/ directory)
- Internal code (markitect/ directory)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

agents/agent-tdd-workflow.md

@@ -99,10 +99,10 @@ The **TDD8 cycle** is an 8-step comprehensive development workflow that extends
 You are the authoritative guide for the TDD8 workflow using the issue-facade system for issue management. You understand how each step builds upon the previous ones and how sidequests can emerge at any stage of any software development project.
 
 **Primary Issue Management Commands:**
-- Issue management via issue-facade: `cd issue-facade && python -m cli.main list`
-- `cd issue-facade && python -m cli.main show ISSUE_NUM` - Show issue details
-- `cd issue-facade && python -m cli.main create "Title" "Description"` - Create new issue
-- `cd issue-facade && python -m cli.main close ISSUE_NUM` - Close completed issue
+- Issue management via issue-facade: `cd capabilities/issue-facade && python -m cli.main list`
+- `cd capabilities/issue-facade && python -m cli.main show ISSUE_NUM` - Show issue details
+- `cd capabilities/issue-facade && python -m cli.main create "Title" "Description"` - Create new issue
+- `cd capabilities/issue-facade && python -m cli.main close ISSUE_NUM` - Close completed issue
 
 **Capability Awareness:**
 - **Before implementing**: Check `CAPABILITY_REGISTRY.md` for existing functionality
@@ -116,7 +116,7 @@ You are the authoritative guide for the TDD8 workflow using the issue-facade sys
 - Tea CLI: `tea issue show NUM` - Show detailed view of specific issue
 
 ### Workspace Management Understanding
-You understand the project structure with issue-facade for issue management:
+You understand the project structure with capabilities/issue-facade for issue management:
 ```
 {workspace_dir}/
 ├── current_issue.json          # Active issue metadata
@@ -157,7 +157,7 @@ You understand the project structure with issue-facade for issue management:
 
 ### TDDAi Framework Components
 **Core Infrastructure:**
-- `issue-facade/` - Universal issue management facade
+- `capabilities/issue-facade/` - Universal issue management facade
   - `workspace.py` - Workspace management
   - `issue_fetcher.py` - Issue API integration
   - `issue_writer.py` - Issue updates via PATCH