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

backend/app/services/wip_title.py

@@ -27,13 +27,10 @@ from .image_tag_apply import insert_image_tags
 
 # image_tag.source stamped on title-heuristic WIP tags — distinct from the other
 # apply sources so provenance stays legible and a future undo can target only these.
-# HARD tier ("WIP"/"work in progress") is high-precision → trains the wip head.
+# Only the artist's own "WIP"/"work in progress" label counts — high-precision, so it
+# trains the wip head. A sketch/doodle/scribble tier (#1474) was retired in milestone
+# 430: a "sketch" is usually finished art, and its 6k tags flooded the review strip.
 WIP_TITLE_SOURCE = "wip_title"
-# SOFT tier (sketch/doodle/scribble, #1474) is LOWER-precision — a finished "sketch"
-# is often not WIP. This source is PROVISIONAL (in training_data._AUTO_SOURCES) so it
-# NEVER trains the wip head; a soft-tagged image that also looks like real content is
-# surfaced by the ring-loud audit for review.
-WIP_TITLE_SOFT_SOURCE = "wip_title_soft"
 
 # A standalone "WIP" / "W.I.P" token, or the phrase "work in progress"
 # (space/underscore/hyphen separated). The letter-boundary lookarounds are what
@@ -45,20 +42,10 @@ _WIP_RE = re.compile(
     re.IGNORECASE,
 )
 
-# Soft tier: sketch / doodle / scribble (+ plurals), letter-boundary anchored so
-# "sketchbook" / "kadoodle" don't trip it. Deliberately conservative — recall is
-# secondary because the soft source doesn't train the head and the ring-loud audit
-# catches false positives.
-_SOFT_WIP_RE = re.compile(
-    r"(?<![A-Za-z])(?:sketch|sketches|doodle|doodles|scribble|scribbles)(?![A-Za-z])",
-    re.IGNORECASE,
-)
-
-# Coarse SQL prefilters for the backfill sweep — narrow the post scan to rows that
+# Coarse SQL prefilter for the backfill sweep — narrows the post scan to rows that
 # COULD match before the precise regex confirms. Case-insensitive ILIKE patterns.
-# Each MUST stay a SUPERSET of its regex or the sweep would silently miss posts.
+# It MUST stay a SUPERSET of the regex or the sweep would silently miss posts.
 WIP_TITLE_SQL_PREFILTER = ("%wip%", "%work%progress%")
-SOFT_WIP_TITLE_SQL_PREFILTER = ("%sketch%", "%doodle%", "%scribble%")
 
 # Chunk bulk inserts so a large sweep can't blow past psycopg's 65535-parameter
 # ceiling (3 params/row → ~21k rows max; 5k stays comfortably under).
@@ -66,19 +53,12 @@ _INSERT_CHUNK = 5000
 
 
 def matches_wip_title(title: str | None) -> bool:
-    """True when a post title explicitly marks it work-in-progress (HARD tier)."""
+    """True when a post title explicitly marks it work-in-progress."""
     if not title:
         return False
     return _WIP_RE.search(title) is not None
 
 
-def matches_soft_wip_title(title: str | None) -> bool:
-    """True when a title carries a SOFT WIP cue (sketch/doodle/scribble, #1474)."""
-    if not title:
-        return False
-    return _SOFT_WIP_RE.search(title) is not None
-
-
 def resolve_wip_tag_id(session: Session) -> int | None:
     """The seeded ``wip`` system tag's id (migration 0075), or None if absent."""
     return session.execute(