fix(suggestions): resolve bare WD14 character names to existing "(Fandom)" tags

WD14 emits bare names (e.g. "Ruby Rose") while curated character/fandom
tags carry a fandom suffix ("Ruby Rose (RWBY)"). Two gaps caused a
duplicate, fandom-less tag to be created when users accepted a WD14
suggestion for an image that already had the curated version:

- Suggestion compute: bare character/copyright suggestions are now
  suppressed when the image already carries a `Name (Fandom)` variant,
  so the duplicate chip no longer surfaces.
- Accept endpoint: if the exact-name lookup misses for character/fandom
  kinds, we try a `Name (%)`-scoped lookup and attach the existing tag
  only when exactly one candidate matches. Zero or multiple matches
  fall through to prior behavior to avoid silently guessing across
  ambiguous fandoms.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

app/services/tag_suggestions.py

@@ -8,6 +8,7 @@ The result is grouped by category and annotated with whether each tag already
 exists in the Tag table (the modal dims disallowed auto-creations).
 """
 from __future__ import annotations
+import re
 from typing import Iterable
 
 from sqlalchemy import select
@@ -106,6 +107,21 @@ def _existing_tag_names() -> set[str]:
     return {row[0] for row in db.session.query(Tag.name).all()}
 
 
+# Matches `Name (Fandom)` — used to recognize that an applied character/copyright
+# tag covers a bare WD14 suggestion like `Name`.
+_FANDOM_SUFFIX_RE = re.compile(r'^(.+?) \([^()]+\)$')
+
+
+def _fandom_suffix_prefixes(names: Iterable[str]) -> set[str]:
+    """Extract the `Name` portion from any `Name (Fandom)` entries in `names`."""
+    out: set[str] = set()
+    for n in names:
+        m = _FANDOM_SUFFIX_RE.match(n)
+        if m:
+            out.add(m.group(1))
+    return out
+
+
 def _wd14_suggestions(image_id: int, cfg: dict, already: set[str]) -> list[dict]:
     wd14_ver = cfg.get('wd14_model_version', _DEFAULTS['wd14_model_version'])
     preds = (
@@ -113,6 +129,11 @@ def _wd14_suggestions(image_id: int, cfg: dict, already: set[str]) -> list[dict]
         .filter_by(image_id=image_id, model_version=wd14_ver)
         .all()
     )
+    # Bare names covered by an already-applied `Name (Fandom)` tag. WD14 emits
+    # bare names (e.g. "Ruby Rose") even when the curated tag is fandom-scoped
+    # ("Ruby Rose (RWBY)"); without this, the same character resurfaces as a
+    # duplicate suggestion and accepting it creates a second, fandom-less tag.
+    applied_fandom_prefixes = _fandom_suffix_prefixes(already)
     out: list[dict] = []
     for p in preds:
         threshold = _category_threshold(p.tag_category, cfg)
@@ -121,6 +142,8 @@ def _wd14_suggestions(image_id: int, cfg: dict, already: set[str]) -> list[dict]
         canonical = _canonicalize_wd14_name(p.tag_name, p.tag_category)
         if canonical in already:
             continue
+        if p.tag_category in ('character', 'copyright') and canonical in applied_fandom_prefixes:
+            continue
         out.append({
             'name': canonical,
             'category': p.tag_category,