POST /turnstone/api/ingest/tautulli accepts Tautulli notification agent
payloads and stores them as log_entries under source 'tautulli'. Severity
maps error->CRITICAL, buffer->WARN, all others->None. Optional bearer token
auth via X-Tautulli-Token header + tautulli_token pref. FTS index rebuilt
as a background task after each write. 28 new tests, all passing.
