feat(ml): presentation-chrome auto-hide sweep + hard-skip + conflict flagging (#141 step 4)

presentation_auto_apply_sweep fires banner/editor-screenshot heads at the FLAT
presentation threshold (source=presentation_auto). Two guards: (1) hard-skip any
image already carrying a human/confirmed content tag — you valued it, so the model
can't bury it; (2) if an auto-hide ALSO scores >= presentation_conflict_threshold
on a content head, hide it but record a PresentationReview row (conflict tag +
score) for the Hidden view.

_auto_apply_heads now excludes system tags, so a graduated wip/banner can't fire
via the content path (and wip never auto-applies at all). presentation_auto added
to _AUTO_SOURCES so auto-hidden chrome never self-trains. Tests: applies,
hard-skip valued, conflict-flag, disabled no-op, ignores wip, content-path
excludes system. Settings UI + scheduling land next.

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

tests/test_presentation_auto_apply.py

@@ -0,0 +1,152 @@
+"""Presentation-chrome auto-hide sweep (#141). numpy-only (no sklearn), so the
+apply + guard logic is tested directly via the sync session."""
+import pytest
+from sqlalchemy import select
+
+from backend.app.models import (
+    HeadAutoApplyRun,
+    ImageRecord,
+    MLSettings,
+    PresentationReview,
+    Tag,
+    TagHead,
+    TagKind,
+)
+from backend.app.models.tag import image_tag
+from backend.app.services.ml.heads import (
+    auto_apply_sweep,
+    presentation_auto_apply_sweep,
+)
+
+pytestmark = pytest.mark.integration
+
+
+def _emb(slot: int) -> list[float]:
+    v = [0.0] * 1152
+    v[slot] = 3.0
+    return v
+
+
+def _img(db, sha: str, emb) -> ImageRecord:
+    img = ImageRecord(
+        path=f"/images/{sha}.jpg", sha256=sha, size_bytes=1, mime="image/jpeg",
+        width=1, height=1, origin="imported_filesystem",
+        integrity_status="unknown", siglip_embedding=emb,
+    )
+    db.add(img)
+    db.flush()
+    return img
+
+
+def _head(db, tag_id: int, slot: int, *, weight=1.0):
+    # weight 3.0 → score sigmoid(3)=0.95 clears the 0.90 presentation floor;
+    # weight 1.0 → sigmoid(1)=0.73 clears the 0.50 conflict floor.
+    s = db.execute(select(MLSettings).where(MLSettings.id == 1)).scalar_one()
+    w = [0.0] * 1152
+    w[slot] = weight
+    db.add(TagHead(
+        tag_id=tag_id, embedding_version=s.embedder_model_version,
+        weights=w, bias=0.0, suggest_threshold=0.5, auto_apply_threshold=0.5,
+        n_pos=60, n_neg=90, ap=0.9, precision_cv=0.98, recall=0.7,
+    ))
+
+
+def _system_tag(db, name):
+    return db.execute(
+        select(Tag).where(Tag.is_system.is_(True), Tag.name == name)
+    ).scalar_one()
+
+
+def _source(db, image_id, tag_id):
+    return db.execute(
+        select(image_tag.c.source)
+        .where(image_tag.c.image_record_id == image_id)
+        .where(image_tag.c.tag_id == tag_id)
+    ).scalar_one_or_none()
+
+
+def test_presentation_sweep_hides_chrome(db_sync):
+    banner = _system_tag(db_sync, "banner")
+    _head(db_sync, banner.id, 0, weight=3.0)
+    img = _img(db_sync, "a" * 64, _emb(0))
+    db_sync.commit()
+    res = presentation_auto_apply_sweep(db_sync)
+    assert res["n_applied"] == 1
+    assert _source(db_sync, img.id, banner.id) == "presentation_auto"
+
+
+def test_presentation_sweep_hard_skips_valued_image(db_sync):
+    # An image the operator already tagged with a content tag is never auto-hidden.
+    banner = _system_tag(db_sync, "banner")
+    _head(db_sync, banner.id, 0, weight=3.0)
+    content = Tag(name="mychar", kind=TagKind.character)
+    db_sync.add(content)
+    db_sync.flush()
+    img = _img(db_sync, "b" * 64, _emb(0))
+    db_sync.execute(image_tag.insert().values(
+        image_record_id=img.id, tag_id=content.id, source="manual"))
+    db_sync.commit()
+    res = presentation_auto_apply_sweep(db_sync)
+    assert res["n_applied"] == 0
+    assert _source(db_sync, img.id, banner.id) is None
+
+
+def test_presentation_sweep_flags_conflict(db_sync):
+    # Matches banner AND scores high on a content head → hidden but flagged with
+    # that content tag as the conflict.
+    banner = _system_tag(db_sync, "banner")
+    _head(db_sync, banner.id, 0, weight=3.0)
+    content = Tag(name="looksreal", kind=TagKind.general)
+    db_sync.add(content)
+    db_sync.flush()
+    _head(db_sync, content.id, 0, weight=1.0)     # content head also fires
+    img = _img(db_sync, "c" * 64, _emb(0))
+    db_sync.commit()
+    res = presentation_auto_apply_sweep(db_sync)
+    assert res["n_applied"] == 1
+    assert res["n_flagged"] == 1
+    assert _source(db_sync, img.id, banner.id) == "presentation_auto"
+    flag = db_sync.execute(
+        select(PresentationReview).where(
+            PresentationReview.image_record_id == img.id,
+            PresentationReview.tag_id == banner.id,
+        )
+    ).scalar_one()
+    assert flag.conflict_tag_id == content.id
+    assert flag.conflict_score >= 0.5
+
+
+def test_presentation_sweep_disabled_is_noop(db_sync):
+    s = db_sync.execute(select(MLSettings).where(MLSettings.id == 1)).scalar_one()
+    s.presentation_auto_apply_enabled = False
+    banner = _system_tag(db_sync, "banner")
+    _head(db_sync, banner.id, 0, weight=3.0)
+    img = _img(db_sync, "d" * 64, _emb(0))
+    db_sync.commit()
+    res = presentation_auto_apply_sweep(db_sync)
+    assert res["n_applied"] == 0
+    assert _source(db_sync, img.id, banner.id) is None
+
+
+def test_presentation_sweep_ignores_wip(db_sync):
+    # wip is a system tag but NOT presentation chrome → never auto-applied.
+    wip = _system_tag(db_sync, "wip")
+    _head(db_sync, wip.id, 0, weight=3.0)
+    img = _img(db_sync, "e" * 64, _emb(0))
+    db_sync.commit()
+    res = presentation_auto_apply_sweep(db_sync)
+    assert res["n_applied"] == 0
+    assert _source(db_sync, img.id, wip.id) is None
+
+
+def test_content_sweep_never_fires_system_tags(db_sync):
+    # A graduated banner (system) head must NOT auto-apply via the content path.
+    banner = _system_tag(db_sync, "banner")
+    _head(db_sync, banner.id, 0, weight=3.0)
+    img = _img(db_sync, "f" * 64, _emb(0))
+    run = HeadAutoApplyRun(dry_run=False, params={}, status="running")
+    db_sync.add(run)
+    db_sync.flush()
+    db_sync.commit()
+    auto_apply_sweep(db_sync, run, dry_run=False)
+    assert _source(db_sync, img.id, banner.id) is None