fix: persist ingester position and profiler cursor across restarts

- Ingester now loads byte-offset from DB on startup (key: ingest_worker_position)
  and saves it after each batch — prevents full re-read on every API restart
- On file truncation/rotation the saved offset is reset to 0
- Profiler worker now loads last_log_id from DB on startup — every restart
  becomes an incremental update instead of a full cold rebuild
- Updated all affected tests to mock get_state/set_state; added new tests
  covering position restore, set_state call, truncation reset, and cursor
  restore/cold-start paths

decnet/profiler/worker.py

@@ -50,6 +50,11 @@ async def attacker_profile_worker(repo: BaseRepository, *, interval: int = 30) -
     """Periodically updates the Attacker table incrementally. Designed to run as an asyncio Task."""
     logger.info("attacker profile worker started interval=%ds", interval)
     state = _WorkerState()
+    _saved_cursor = await repo.get_state(_STATE_KEY)
+    if _saved_cursor:
+        state.last_log_id = _saved_cursor.get("last_log_id", 0)
+        state.initialized = True
+        logger.info("attacker worker: resumed from cursor last_log_id=%d", state.last_log_id)
     while True:
         await asyncio.sleep(interval)
         try: