feat(phase-4a): complete Phase 3 implementation and gap analysis

Merges Phase 4a work including:

Implementation:
- Metadata discovery endpoint (/api/.well-known/oauth-authorization-server)
- h-app microformat parser service
- Enhanced authorization endpoint with client info display
- Configuration management system
- Dependency injection framework

Documentation:
- Comprehensive gap analysis for v1.0.0 compliance
- Phase 4a clarifications on development approach
- Phase 4-5 critical components breakdown

Testing:
- Unit tests for h-app parser (308 lines, comprehensive coverage)
- Unit tests for metadata endpoint (134 lines)
- Unit tests for configuration system (18 lines)
- Integration test updates

All tests passing with high coverage. Ready for Phase 4b security hardening.

pyproject.toml

@@ -31,6 +31,7 @@ dependencies = [
     "aiosmtplib>=3.0.0",
     "beautifulsoup4>=4.12.0",
     "jinja2>=3.1.0",
+    "mf2py>=2.0.0",
 ]
 
 [project.optional-dependencies]