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/server.py

@@ -565,7 +565,7 @@ async def fable_get_app_logs(
     """Fetch Fable application logs. Requires an admin-scoped API key.
 
     Args:
-        category: Log category — "error" (default), "audit", or "usage".
+        category: Log category — "error" (default), "audit", "usage", or "generation".
         limit: Maximum number of log entries to return.
         search: Optional keyword filter matched against action, endpoint, username, details.