feat: re-integrate issue-facade with family-based architecture

Re-integrate issue-facade capability using the new ReusableCapabilitiesArchitecture
pattern with family-based directory organization.

New Structure:
- _issue-tracking/issue-facade/ (family-based organization)
- Uses underscore prefix to signal integrated capability
- Implements ReusableCapabilitiesArchitecture v0.1

Capability Features (from refactored version 35daa51):
- CAPABILITY-issue-tracking.yaml (explicit family declaration)
- feedback/ directory (visible user interface)
- .capability/detach script (clean removal facility)
- ReusableCapabilitiesArchitecture.md (complete specification)

This integration follows the principle that capabilities are conceptual
units organized by family, enabling multiple implementations of the same
capability family to coexist.

Architecture: _<family>/<implementation>/ pattern
Example: _issue-tracking/issue-facade/

See _issue-tracking/issue-facade/ReusableCapabilitiesArchitecture.md for details.

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.gitmodules

@@ -8,3 +8,7 @@
 [submodule "capabilities/testdrive-jsui"]
 	path = capabilities/testdrive-jsui
 	url = http://92.205.130.254:32166/coulomb/testdrive-jsui.git
+[submodule "_issue-tracking/issue-facade"]
+	path = _issue-tracking/issue-facade
+	url = http://92.205.130.254:32166/coulomb/issue-facade.git
+	branch = main