The retain outbox callback was passing context.tenant_id (raw UUID like
0f3ad4ec-8b88-...) instead of the PostgreSQL schema name (tenant_0f3ad4ec_...).
This caused the webhook manager to query a non-existent schema, triggering a
PostgreSQL error that silently aborted the entire retain transaction — rolling
back all inserted memory data with no clear indication of data loss.
Fixed both the async worker path (memory_engine.py) and sync HTTP path (http.py)
to use _current_schema.get() which holds the correct tenant-prefixed schema name.
Also changed fire_event_with_conn to re-raise exceptions instead of swallowing
them, since errors inside a caller's transaction poison it irreversibly.
75b95106ba