feat(ml): presentation auto-hide settings + review table (#141 step 3)

MLSettings gains presentation_auto_apply_enabled / _threshold (default 0.90) +
presentation_conflict_threshold (default 0.50): banner/editor auto-hide with a
FLAT threshold (decoupled from content-head graduation), plus the "also looks
like content" conflict cut. New presentation_review table (image, presentation
tag, conflict tag + score, created/resolved_at) records auto-hides flagged for
review. Migration 0082 (columns + table), ml_admin API (editable + get_settings
+ _validate bounds), settings roundtrip/bounds test. The sweep that reads these
knobs + the Settings UI land in step 4.

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

tests/test_api_ml_admin.py

@@ -81,6 +81,35 @@ async def test_detector_settings_defaults_patch_and_validation(client):
         "/api/ml/settings", json={"detector_max_regions": 0})).status_code == 400
 
 
+@pytest.mark.asyncio
+async def test_presentation_settings_defaults_patch_and_validation(client):
+    # #141: presentation-chrome auto-hide knobs (banner/editor auto-apply +
+    # the "also looks like content" conflict threshold) are exposed + editable.
+    body = await (await client.get("/api/ml/settings")).get_json()
+    assert body["presentation_auto_apply_enabled"] is True
+    assert body["presentation_auto_apply_threshold"] == 0.90
+    assert body["presentation_conflict_threshold"] == 0.50
+
+    ok = await client.patch("/api/ml/settings", json={
+        "presentation_auto_apply_enabled": False,
+        "presentation_auto_apply_threshold": 0.95,
+        "presentation_conflict_threshold": 0.4,
+    })
+    assert ok.status_code == 200
+    out = await ok.get_json()
+    assert out["presentation_auto_apply_enabled"] is False
+    assert out["presentation_auto_apply_threshold"] == 0.95
+    assert out["presentation_conflict_threshold"] == 0.4
+
+    # Auto-apply threshold below the floor + conflict cut above 1 are rejected.
+    assert (await client.patch(
+        "/api/ml/settings",
+        json={"presentation_auto_apply_threshold": 0.4})).status_code == 400
+    assert (await client.patch(
+        "/api/ml/settings",
+        json={"presentation_conflict_threshold": 1.5})).status_code == 400
+
+
 @pytest.mark.asyncio
 async def test_embedder_models_list(client):
     # #1203: the dropdown reads the supported-model list from the server.