Initial commit: AirCoding V1.0.0 Alpha architecture baseline

Complete architecture document set with multi-model review remediation:
- Frozen interface contracts, runtime semantics, DB schemas
- Event/tool/error/provider registries
- Scheduler and main agent state machines
- C4 module/code views, solution architecture, baseline V1
- Multi-model review reports and joint assessment
- Phase-gate remediation complete (P0/P1/P2/UX resolved)
- Implementation plan with T-000A through T-045
- Reference folders kept as placeholders only

reference/claude-hud-0.0.12/.github/pull_request_template.md

@@ -0,0 +1,11 @@
+## Summary
+
+## Testing
+
+- [ ] `npm test`
+- [ ] `npm run test:coverage`
+
+## Checklist
+
+- [ ] Tests updated or not needed
+- [ ] Docs updated if behavior changed