🩹(backend) ignore non-recording uploads in storage webhook handler

With the introduction of background file uploads, a misconfigured
MinIO webhook could trigger the storage hook endpoint for unrelated
files.

While the dev setup now filters events via the MinIO lifecycle
configuration, add a safeguard at the application level.

Enforce a stricter filepath regex when parsing storage hook events
and ignore files outside the recording output directory.

Return a clean 200 response to acknowledge the webhook while
avoiding unnecessary processing.

src/backend/core/api/viewsets.py

@@ -38,6 +38,7 @@ from core.recording.enums import FileExtension
 from core.recording.event.authentication import StorageEventAuthentication
 from core.recording.event.exceptions import (
     InvalidBucketError,
+    InvalidFilepathError,
     InvalidFileTypeError,
     ParsingEventDataError,
 )
@@ -761,6 +762,11 @@ class RecordingViewSet(
         except InvalidBucketError as e:
             raise drf_exceptions.PermissionDenied("Invalid bucket specified") from e
 
+        except InvalidFilepathError as e:
+            return drf_response.Response(
+                {"message": f"Ignore this filepath, {e}"},
+            )
+
         except InvalidFileTypeError as e:
             return drf_response.Response(
                 {"message": f"Ignore this file type, {e}"},