Backend returns metadata, ai_moderation_flags, and ai_categories as raw
JSON strings (PostgreSQL JSONB cast to string). Frontend expected parsed
structs/arrays, causing serde to fail silently — entire PageResult parse
failed and user saw empty message list with no error indicator.
Add custom deserialize_with handler (from_json_string_or_value) that
transparently handles null / direct value / JSON-string cases for the
three affected fields.
asepharyana
e73abf596d