feat: implement 15 production items (SSE, security, observability, features, infra)

Performance:
- SSE dashboard streaming endpoint (GET /v1/admin/status/stream)
- Web Worker for markdown rendering (offload from main thread)
- IndexedDB chat persistence (replace localStorage, 500msg support)

Security:
- CSRF protection middleware (Origin/Referer validation)
- Content Security Policy + security headers middleware
- API key rotation endpoint (POST /v1/admin/keys/rotate)

Observability:
- OpenTelemetry tracing with graceful NoOp fallback
- Structured error codes (FAGI-xxxx taxonomy with ErrorResponse schema)
- Audit log export (CSV + JSON at /v1/admin/audit/export/*)

Features:
- Multi-session management hook (parallel conversations)
- Conversation export (markdown/JSON/text download + clipboard)
- Head customization UI (enable/disable + weight sliders for 12 heads)

Infrastructure:
- Kubernetes Helm chart (Deployment, Service, HPA, Ingress)
- Database migration versioning (generate, verify commands)
- Blue-green deployment manifests (color-based traffic switching)

Tests: 598 Python + 56 frontend = 654 total, 0 ruff errors
Co-Authored-By: Nakamoto, S <defi@defi-oracle.io>

fusionagi/api/routes/__init__.py

@@ -3,7 +3,10 @@
 from fastapi import APIRouter
 
 from fusionagi.api.routes.admin import router as admin_router
+from fusionagi.api.routes.audit_export import router as audit_router
 from fusionagi.api.routes.backup import router as backup_router
+from fusionagi.api.routes.dashboard_sse import router as dashboard_sse_router
+from fusionagi.api.routes.key_rotation import router as key_rotation_router
 from fusionagi.api.routes.openai_compat import router as openai_compat_router
 from fusionagi.api.routes.plugins import router as plugins_router
 from fusionagi.api.routes.sessions import router as sessions_router
@@ -19,4 +22,7 @@ router.include_router(admin_router, prefix="/admin", tags=["admin"])
 router.include_router(tenant_router, prefix="/admin", tags=["tenants"])
 router.include_router(plugins_router, prefix="/admin", tags=["plugins"])
 router.include_router(backup_router, prefix="/admin", tags=["backup"])
+router.include_router(dashboard_sse_router, prefix="/admin", tags=["dashboard-sse"])
+router.include_router(key_rotation_router, prefix="/admin", tags=["key-rotation"])
+router.include_router(audit_router, prefix="/admin", tags=["audit"])
 router.include_router(openai_compat_router)