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_retire_soft_wip_migration.py

@@ -0,0 +1,90 @@
+"""Migration 0112 (milestone 430, #4428): retiring the sketch/doodle WIP title tier.
+
+Runs the migration's data step against real rows. The soft tags the operator stood
+behind (confirmed, or kept through the review strip) survive as `manual`; the rest go,
+and so do the unresolved review cards whose tag went with them. Hard title tags and
+their flags are untouched.
+"""
+import importlib.util
+from datetime import UTC, datetime
+from pathlib import Path
+
+import pytest
+from sqlalchemy import select
+
+from backend.app.models import PresentationReview, TagPositiveConfirmation
+from backend.app.models.tag import image_tag
+from backend.app.services.wip_title import resolve_wip_tag_id
+from tests.factories import make_image as _img
+
+pytestmark = pytest.mark.integration
+
+_MIGRATION = (
+    Path(__file__).resolve().parents[1]
+    / "alembic" / "versions" / "0112_retire_soft_wip_title.py"
+)
+
+
+def _retire():
+    spec = importlib.util.spec_from_file_location("m0112", _MIGRATION)
+    mod = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(mod)
+    return mod.retire_soft_wip_tags
+
+
+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 _review(db, image_id, tag_id):
+    return db.execute(
+        select(PresentationReview)
+        .where(PresentationReview.image_record_id == image_id)
+        .where(PresentationReview.tag_id == tag_id)
+    ).scalar_one_or_none()
+
+
+def _flag(db, image_id, tag_id, *, resolved):
+    db.add(PresentationReview(
+        image_record_id=image_id, tag_id=tag_id, conflict_score=0.8, mode="process",
+        resolved_at=datetime.now(UTC) if resolved else None,
+    ))
+
+
+def test_retire_soft_wip_keeps_human_judged_and_clears_the_rest(db_sync):
+    wip = resolve_wip_tag_id(db_sync)
+    plain = _img(db_sync, "a" * 64)       # soft, never looked at → removed
+    confirmed = _img(db_sync, "b" * 64)   # soft + confirmed → kept as manual
+    kept = _img(db_sync, "c" * 64)        # soft + "Keep tag" in the strip → manual
+    pending = _img(db_sync, "d" * 64)     # soft + open card → tag and card removed
+    hard = _img(db_sync, "e" * 64)        # hard title tag + open card → untouched
+    for img in (plain, confirmed, kept, pending):
+        db_sync.execute(image_tag.insert().values(
+            image_record_id=img.id, tag_id=wip, source="wip_title_soft"))
+    db_sync.execute(image_tag.insert().values(
+        image_record_id=hard.id, tag_id=wip, source="wip_title"))
+    db_sync.add(TagPositiveConfirmation(image_record_id=confirmed.id, tag_id=wip))
+    _flag(db_sync, kept.id, wip, resolved=True)
+    _flag(db_sync, pending.id, wip, resolved=False)
+    _flag(db_sync, hard.id, wip, resolved=False)
+    db_sync.flush()
+
+    _retire()(db_sync.connection())
+    db_sync.expire_all()
+
+    assert _source(db_sync, plain.id, wip) is None
+    assert _source(db_sync, confirmed.id, wip) == "manual"
+    assert _source(db_sync, kept.id, wip) == "manual"
+    assert _source(db_sync, pending.id, wip) is None
+    assert _source(db_sync, hard.id, wip) == "wip_title"
+
+    assert _review(db_sync, pending.id, wip) is None
+    assert _review(db_sync, kept.id, wip) is not None     # resolved history stays
+    assert _review(db_sync, hard.id, wip) is not None     # its tag is still on
+    assert db_sync.execute(
+        select(image_tag.c.image_record_id).where(image_tag.c.source == "wip_title_soft")
+    ).first() is None