fix(mavvrik): guard startup against decryption failure + sanitize 500 error responses

- proxy_server.py: wrap is_mavvrik_setup() in try/except so a ValueError
  from AES decryption failure (e.g. master-key rotation) logs a warning
  and skips the background job instead of crashing startup
- mavvrik_endpoints.py: catch-all 500 handler now returns type(exc).__name__
  instead of str(exc) to prevent Postgres DSNs leaking into API responses

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

litellm/proxy/proxy_server.py

@@ -7747,7 +7747,15 @@ class ProxyStartupEvent:
             is_mavvrik_setup,
         )
 
-        if await is_mavvrik_setup():
+        try:
+            _mavvrik_ready = await is_mavvrik_setup()
+        except Exception as _e:
+            verbose_proxy_logger.warning(
+                "mavvrik: skipping startup — is_mavvrik_setup() failed: %s", _e
+            )
+            _mavvrik_ready = False
+
+        if _mavvrik_ready:
             from litellm.constants import (  # noqa: PLC0415
                 MAVVRIK_EXPORT_INTERVAL_MINUTES,
                 MAVVRIK_EXPORT_USAGE_DATA_JOB_NAME,

litellm/proxy/spend_tracking/mavvrik_endpoints.py

@@ -85,7 +85,11 @@ async def _mavvrik_errors() -> AsyncIterator[None]:
     except ValueError as exc:
         raise HTTPException(status_code=400, detail={"error": str(exc)}) from exc
     except Exception as exc:
-        raise HTTPException(status_code=500, detail={"error": str(exc)}) from exc
+        # Use only the exception type name to avoid leaking internal details
+        # (e.g. Postgres DSNs, hostnames) into API responses.
+        raise HTTPException(
+            status_code=500, detail={"error": type(exc).__name__}
+        ) from exc
 
 
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