feat: retire the sketch/doodle WIP title tier, and the review strip asks "Is this a WIP?" (milestone 430)

The soft tier (#1474) tagged `wip` on any post titled sketch, doodle or
scribble: 6,096 of the library's 8,876 wip tags. Its conflict audit flagged
most of them, because finished art scores >= 0.5 on some content head,
which filled the Gallery strip with 2,086 cards. A "sketch" is usually
finished work, so the operator retired the tier. The artist's own
"WIP" / "work in progress" title rule and human wip tags stay.

- Removed: the soft matcher, source and prefilter; the importer and backfill
  soft branches; soft_wip_conflict_audit with its task and beat; the
  wip_soft_title_tagging_enabled setting, API field and toggle; and
  wip_title_soft from _AUTO_SOURCES.
- Migration 0112: a soft tag the operator confirmed, or kept from the strip,
  becomes `manual`. Every other soft tag is deleted, along with the open
  review cards whose tag is gone. The column is dropped.
- Review strip (#4424): each card asks "Is this a WIP?" (or banner, and so on),
  and the buttons read "Is a WIP" / "Is not a WIP". The content tag it also
  scored on is shown as the reason it was flagged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LVjrnpQjRgHdvq95rASoiR

tests/test_process_auto_apply.py

@@ -126,53 +126,17 @@ def test_process_sweep_flags_conflict_with_process_mode(db_sync):
 
 
 def test_process_auto_source_never_trains_head(db_sync):
-    # The runaway break: provisional wip tags (process sweep 'process_auto', soft
-    # title 'wip_title_soft') are NOT training positives; a HARD title-heuristic /
-    # manual one IS. So the head learns only from trusted labels, never its own
-    # output or the low-precision sketch/doodle tier (#1464 + #1474).
+    # The runaway break: provisional wip tags (process sweep 'process_auto') are NOT
+    # training positives; a title-heuristic / manual one IS. So the head learns only
+    # from trusted labels, never its own output (#1464).
     wip = _system_tag(db_sync, "wip")
     auto_img = _img(db_sync, "f" * 64, _emb(0))
-    soft_img = _img(db_sync, "9" * 64, _emb(2))
     title_img = _img(db_sync, "0" * 64, _emb(1))
     db_sync.execute(image_tag.insert().values(
         image_record_id=auto_img.id, tag_id=wip.id, source="process_auto"))
-    db_sync.execute(image_tag.insert().values(
-        image_record_id=soft_img.id, tag_id=wip.id, source="wip_title_soft"))
     db_sync.execute(image_tag.insert().values(
         image_record_id=title_img.id, tag_id=wip.id, source="wip_title"))
     db_sync.commit()
     positives = set(_ids_with_tag(db_sync, wip.id))
     assert title_img.id in positives       # trusted HARD label trains the head
     assert auto_img.id not in positives    # its own auto-applied output does NOT
-    assert soft_img.id not in positives    # low-precision soft tier does NOT
-
-
-def test_soft_wip_conflict_audit_flags_ring_loud(db_sync):
-    # A soft-tagged image (sketch/doodle title) that ALSO scores high on a content
-    # head is probably finished art mis-tagged — flagged for review; a quiet one is not.
-    from backend.app.services.ml.heads import soft_wip_conflict_audit
-
-    s = db_sync.execute(select(MLSettings).where(MLSettings.id == 1)).scalar_one()
-    s.process_conflict_threshold = 0.6
-    wip = _system_tag(db_sync, "wip")
-    content = Tag(name="looksreal", kind=TagKind.general)
-    db_sync.add(content)
-    db_sync.flush()
-    _head(db_sync, content.id, 0, weight=1.0)   # sigmoid(1)=0.73 > 0.6 conflict
-    ring = _img(db_sync, "1" * 64, _emb(0))      # scores on the content head
-    quiet = _img(db_sync, "2" * 64, _emb(5))     # orthogonal → 0.5 < 0.6
-    for img in (ring, quiet):
-        db_sync.execute(image_tag.insert().values(
-            image_record_id=img.id, tag_id=wip.id, source="wip_title_soft"))
-    db_sync.commit()
-
-    res = soft_wip_conflict_audit(db_sync)
-    assert res["n_flagged"] == 1
-    flag = db_sync.execute(
-        select(PresentationReview).where(PresentationReview.image_record_id == ring.id)
-    ).scalar_one()
-    assert flag.mode == "process"
-    assert flag.conflict_tag_id == content.id
-    assert db_sync.execute(
-        select(PresentationReview).where(PresentationReview.image_record_id == quiet.id)
-    ).scalar_one_or_none() is None