Add admin panel, WebSocket support, and API versioning

Introduce an admin portal (React + Nginx), WebSocket routing, and
API versioning middleware with `/api/v1/` prefix deprecation.
Add master API key authentication, new Prometheus metrics for AI
token consumption and active WebSockets, and extend S3 config
with a public endpoint URL. Update test paths and fixtures to
align with the new routing structure.

tests/conftest.py

@@ -55,7 +55,7 @@ app.dependency_overrides[get_db] = override_get_db
 # Mock ARQ pool et Redis pour les tests (pas de Redis requis)
 # ─────────────────────────────────────────────────────────────
 
-from unittest.mock import AsyncMock
+from unittest.mock import AsyncMock, patch
 
 _mock_arq_pool = AsyncMock()
 _mock_arq_pool.enqueue_job = AsyncMock(return_value=None)
@@ -75,12 +75,14 @@ app.state.redis = _mock_redis
 
 @pytest_asyncio.fixture(autouse=True)
 async def setup_database():
-    """Crée et détruit toutes les tables avant/après chaque test."""
-    async with test_engine.begin() as conn:
-        await conn.run_sync(Base.metadata.create_all)
-    yield
-    async with test_engine.begin() as conn:
-        await conn.run_sync(Base.metadata.drop_all)
+    """Crée et détruit toutes les tables avant/après chaque test. Patch also STORAGE_BACKEND."""
+    with patch("app.services.storage.settings.STORAGE_BACKEND", "local"), \
+         patch("app.config.settings.STORAGE_BACKEND", "local"):
+        async with test_engine.begin() as conn:
+            await conn.run_sync(Base.metadata.create_all)
+        yield
+        async with test_engine.begin() as conn:
+            await conn.run_sync(Base.metadata.drop_all)
 
 
 @pytest_asyncio.fixture