fix(fable-mcp): fix streaming error handling and bump timeout for SSE

- stream_get now reads error responses before calling _raise_for_status
  (httpx raises on .json()/.text access inside an unread stream context)
- Raise read timeout to 120s (was 30s) so generation streams don't timeout
- Document "generation" as a valid category for fable_get_app_logs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fable-mcp/fable_mcp/tools/admin.py

@@ -12,7 +12,7 @@ async def get_app_logs(
 ) -> dict:
     """Fetch application logs from Fable. Requires an admin-scoped API key.
 
-    category: "error" | "audit" | "usage" (default: "error")
+    category: "error" | "audit" | "usage" | "generation" (default: "error")
     """
     params: dict = {"category": category, "limit": limit}
     if search: