test(cleanup): fix prune-spares-fandom fixture — used character keeps fandom alive

The character pointing at the fandom had no image associations, so it was
itself unused and inflated the dry-run count to 2. Tag it on a real image so
it is used (the real-world shape) — the fandom survives via a live character.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_cleanup_service.py

@@ -362,7 +362,9 @@ def test_prune_unused_tags_commit_deletes_them(db_sync, tmp_path):
     assert "bye" not in surviving_names
 
 
-def test_prune_unused_tags_commit_spares_fandom_and_chaptered_series(db_sync):
+def test_prune_unused_tags_commit_spares_fandom_and_chaptered_series(
+    db_sync, tmp_path,
+):
     # The LIVE delete (not just the preview) must use the same predicate — it
     # previously had only the image_tag/series_page checks and deleted every
     # fandom the preview correctly excluded (operator-flagged 2026-06-08, real
@@ -370,6 +372,16 @@ def test_prune_unused_tags_commit_spares_fandom_and_chaptered_series(db_sync):
     fandom = _make_tag(db_sync, name="Creux", kind=TagKind.fandom)
     char = _make_tag(db_sync, name="OcChar", kind=TagKind.character)
     char.fandom_id = fandom.id
+    # The character itself is used (tagged on an image) — that is the real-world
+    # shape: characters survive on their image_tag rows, and the fandom they
+    # point at must survive with them.
+    a = _make_artist(db_sync, slug="psf")
+    img = _make_image(
+        db_sync, artist=a, path=str(tmp_path / "c.jpg"), sha256="d" * 64,
+    )
+    db_sync.execute(image_tag.insert().values(
+        image_record_id=img.id, tag_id=char.id,
+    ))
     series = _make_tag(db_sync, name="EmptySeries", kind=TagKind.series)
     db_sync.add(SeriesChapter(series_tag_id=series.id, chapter_number=1))
     _make_tag(db_sync, name="GenuinelyUnused")
@@ -381,6 +393,7 @@ def test_prune_unused_tags_commit_spares_fandom_and_chaptered_series(db_sync):
     assert result["deleted"] == 1
 
     surviving = db_sync.execute(select(Tag.name)).scalars().all()
+    assert "OcChar" in surviving         # used character
     assert "Creux" in surviving          # fandom referenced by a character
     assert "EmptySeries" in surviving    # series referenced by a chapter
     assert "GenuinelyUnused" not in surviving