feat(ml): schedule presentation auto-hide sweep + retention (#141 step 6)

scheduled_presentation_auto_apply (daily beat) runs presentation_auto_apply_sweep
— idempotent, so an interrupted run just re-runs next cycle (that's the recovery),
wall-clock bounded by soft/hard task time limits. prune_presentation_reviews
(daily beat) drops RESOLVED review flags older than 30 days (rule 89 retention).
Tests run both tasks via a monkeypatched session factory. Milestone 141 complete:
the presentation-chrome auto-hide + conflict-flagged review is now live end-to-end.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

backend/app/celery_app.py

@@ -152,6 +152,15 @@ def make_celery() -> Celery:
                 "schedule": 86400.0,  # soft auto-apply: drop auto-tags now below
                 # their threshold (m139); no-op unless the auto-apply switch is on
             },
+            "presentation-auto-apply-daily": {
+                "task": "backend.app.tasks.ml.scheduled_presentation_auto_apply",
+                "schedule": 86400.0,  # auto-hide banner/editor chrome (#141);
+                # no-op unless presentation_auto_apply_enabled
+            },
+            "prune-presentation-reviews-daily": {
+                "task": "backend.app.tasks.ml.prune_presentation_reviews",
+                "schedule": 86400.0,  # retention: drop resolved review flags >30d
+            },
             "snapshot-head-metrics-daily": {
                 "task": "backend.app.tasks.maintenance.snapshot_head_metrics",
                 "schedule": 86400.0,

backend/app/tasks/ml.py

@@ -594,6 +594,46 @@ def scheduled_ccip_auto_apply() -> str:
         return f"applied={applied}"
 
 
+@celery.task(
+    name="backend.app.tasks.ml.scheduled_presentation_auto_apply",
+    soft_time_limit=1800, time_limit=2100,
+)
+def scheduled_presentation_auto_apply() -> str:
+    """Auto-hide presentation chrome (banner / editor screenshot) on a daily
+    passive sweep (#141). No-op unless presentation_auto_apply_enabled. Idempotent
+    — already-hidden images are skipped — so an interrupted run simply re-runs next
+    cycle (that IS the recovery). Wall-clock bounded by the task time limits."""
+    from ..services.ml.heads import presentation_auto_apply_sweep
+
+    SessionLocal = _sync_session_factory()
+    with SessionLocal() as session:
+        result = presentation_auto_apply_sweep(session)
+    return f"applied={result['n_applied']} flagged={result['n_flagged']}"
+
+
+@celery.task(name="backend.app.tasks.ml.prune_presentation_reviews")
+def prune_presentation_reviews() -> str:
+    """Retention (rule 89): drop RESOLVED presentation-review flags older than 30
+    days — the operator has acted on them, so they're just history (#141)."""
+    from datetime import UTC, datetime, timedelta
+
+    from sqlalchemy import delete as sa_delete
+
+    from ..models import PresentationReview
+
+    cutoff = datetime.now(UTC) - timedelta(days=30)
+    SessionLocal = _sync_session_factory()
+    with SessionLocal() as session:
+        res = session.execute(
+            sa_delete(PresentationReview).where(
+                PresentationReview.resolved_at.is_not(None),
+                PresentationReview.resolved_at < cutoff,
+            )
+        )
+        session.commit()
+    return f"pruned={res.rowcount}"
+
+
 @celery.task(
     name="backend.app.tasks.ml.scheduled_retract_auto_tags",
     soft_time_limit=1800, time_limit=2100,