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.

sdk/imago_client/resources/ai.py

@@ -0,0 +1,25 @@
+"""
+AI endpoints interaction.
+"""
+from typing import Any, Dict
+from httpx import AsyncClient
+
+from ..utils import with_retry
+
+class AIResource:
+    """Resource defining AI generative operations."""
+    def __init__(self, client: AsyncClient):
+        self._client = client
+
+    async def _handle_request(self, method: str, path: str, **kwargs) -> Any:
+        async def _req():
+             resp = await self._client.request(method, path, **kwargs)
+             resp.raise_for_status()
+             return resp.json()
+        return await with_retry(_req)
+
+    async def summarize_url(self, url: str, language: str = "français") -> Dict[str, Any]:
+        return await self._handle_request("POST", "/api/v1/ai/summarize", json={"url": url, "language": language})
+    
+    async def draft_task(self, description: str, context: str = "") -> Dict[str, Any]:
+        return await self._handle_request("POST", "/api/v1/ai/draft-task", json={"description": description, "context": context})