Complete all 37 items: frontend UI, backend stubs, infrastructure, docs, tests

Frontend (items 1-10):
- WebSocket streaming integration with useWebSocket hook
- Admin Dashboard UI (status, voices, agents, governance tabs)
- Voice playback UI (TTS/STT integration)
- Settings/Preferences page (conversation style, sliders)
- Responsive/mobile layout (breakpoints at 480px, 768px)
- Dark/light theme with CSS variables and localStorage
- Error handling & loading states (retry, empty state, disabled input)
- Authentication UI (login page, Bearer token, logout)
- Head visualization improvements (active/speaking states, animations)
- Consequence/Ethics dashboard (lessons, consequences, insights tabs)

Backend stubs (items 11-21):
- Tool connectors: DocsConnector (text/md/PDF), DBConnector (SQLite/Postgres), CodeRunnerConnector (Python/JS/Bash/Ruby sandboxed)
- STT adapter: WhisperSTTAdapter, AzureSTTAdapter
- Multi-modal interface adapters: Visual, Haptic, Gesture, Biometric
- SSE streaming endpoint (/v1/sessions/{id}/stream/sse)
- Multi-tenant support (X-Tenant-ID header, tenant CRUD)
- Plugin marketplace/registry (register, install, list)
- Backup/restore endpoints
- Versioned API negotiation (Accept-Version header, deprecation)

Infrastructure (items 22-26):
- docker-compose.yml (API + Postgres + Redis + frontend)
- .env.example with all configurable vars
- gunicorn.conf.py production ASGI config
- Prometheus metrics collector and /metrics endpoint
- Structured JSON logging configuration

Documentation (items 27-29):
- Architecture docs with module layout and subsystem descriptions
- Quickstart guide with setup, API tour, and test instructions

Tests (items 30-32):
- Integration tests: 25 end-to-end API tests
- Frontend tests: 10 Vitest tests for hooks (useTheme, useAuth)
- Load/performance tests: latency and throughput benchmarks
- Connector tests: 16 tests for Docs, DB, CodeRunner
- Multi-modal adapter tests: 9 tests
- Metrics collector tests: 5 tests
- STT adapter tests: 2 tests

511 Python tests passing, 10 frontend tests passing, 0 ruff errors.

Co-Authored-By: Nakamoto, S <defi@defi-oracle.io>

fusionagi/api/app.py

@@ -1,7 +1,10 @@
-"""FastAPI application factory for FusionAGI Dvādaśa API."""
+"""FastAPI application factory for FusionAGI Dvādaśa API.
+
+Includes versioned API negotiation, metrics, and CORS support."""
 
 from __future__ import annotations
 
+import json
 import os
 import time
 from collections import defaultdict
@@ -10,6 +13,11 @@ from typing import Any
 
 from fusionagi._logger import logger
 from fusionagi.api.dependencies import SessionStore, default_orchestrator, set_app_state
+from fusionagi.api.metrics import get_metrics, metrics_enabled
+
+API_VERSION = "1"
+SUPPORTED_VERSIONS = ["1"]
+DEPRECATED_VERSIONS: list[str] = []
 
 
 def create_app(
@@ -106,11 +114,68 @@ def create_app(
 
     app.add_middleware(RateLimitMiddleware)
 
+    # --- Version negotiation middleware ---
+    class VersionMiddleware(BaseHTTPMiddleware):
+        """API version negotiation via Accept-Version header.
+
+        Adds X-API-Version and deprecation warnings to responses.
+        """
+
+        async def dispatch(self, request: Request, call_next: Any) -> Response:
+            requested = request.headers.get("accept-version", API_VERSION)
+            if requested not in SUPPORTED_VERSIONS:
+                return Response(
+                    content=json.dumps({
+                        "detail": f"Unsupported API version: {requested}",
+                        "supported_versions": SUPPORTED_VERSIONS,
+                    }),
+                    status_code=400,
+                    media_type="application/json",
+                )
+            response = await call_next(request)
+            response.headers["X-API-Version"] = requested
+            if requested in DEPRECATED_VERSIONS:
+                response.headers["Deprecation"] = "true"
+                response.headers["Sunset"] = "2026-12-31"
+            return response  # type: ignore[no-any-return]
+
+    app.add_middleware(VersionMiddleware)
+
+    # --- Metrics middleware ---
+    if metrics_enabled():
+        class MetricsMiddleware(BaseHTTPMiddleware):
+            async def dispatch(self, request: Request, call_next: Any) -> Response:
+                m = get_metrics()
+                m.inc("http_requests_total", labels={"method": request.method, "path": request.url.path})
+                start = time.monotonic()
+                response = await call_next(request)
+                duration = time.monotonic() - start
+                m.observe("http_request_duration_seconds", duration, labels={"path": request.url.path})
+                m.inc("http_responses_total", labels={"status": str(response.status_code)})
+                return response  # type: ignore[no-any-return]
+
+        app.add_middleware(MetricsMiddleware)
+
     # --- Routes ---
     from fusionagi.api.routes import router as api_router
 
     app.include_router(api_router, prefix="/v1", tags=["dvadasa"])
 
+    # Metrics endpoint
+    if metrics_enabled():
+        @app.get("/metrics", tags=["monitoring"])
+        def metrics_endpoint() -> dict[str, Any]:
+            return get_metrics().snapshot()
+
+    # Version info endpoint
+    @app.get("/version", tags=["meta"])
+    def version_info() -> dict[str, Any]:
+        return {
+            "current_version": API_VERSION,
+            "supported_versions": SUPPORTED_VERSIONS,
+            "deprecated_versions": DEPRECATED_VERSIONS,
+        }
+
     if cors_origins is not None:
         try:
             from fastapi.middleware.cors import CORSMiddleware