fix: clean output dir per run, fix cron inline comment, clarify volume placeholder

- executor.py: wipe person output dir before each run so stale crops
  from previous runs don't accumulate on disk
- compose.yml: move inline comment off CRON_SCHEDULE value (croniter
  would parse the comment text as part of the expression)
- compose.yml: add note clarifying <pool> placeholder in volume paths

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

compose.yml

@@ -25,10 +25,12 @@ services:
 
       # ── Scheduling ──
       # Cron expression (unset = run once and exit)
-      - CRON_SCHEDULE=0 3 * * 0    # Every Sunday at 3 AM
-      # - CRON_SCHEDULE=0 3 1 * *  # 1st of every month at 3 AM
-      # - CRON_SCHEDULE=*/30 * * * *  # Every 30 minutes (testing)
+      # Every Sunday at 3 AM:
+      - CRON_SCHEDULE=0 3 * * 0
+      # - CRON_SCHEDULE=0 3 1 * *
+      # - CRON_SCHEDULE=*/30 * * * *
     volumes:
+      # Replace <pool> with your TrueNAS pool name, e.g. /mnt/tank/if-curator/...
       - /mnt/<pool>/if-curator/models:/models
       - /mnt/<pool>/if-curator/embeddings:/app/.if_cache
       - /mnt/<pool>/if-curator/output:/app/output