feat(v3 library): show the author's romaji, not blank/native script (English base)

Two changes so an English-speaking base never sees a blank name or native script:

- Filename romaji fallback: a blank-artist CDLC pack ("Artist_Title_v1_p") shows
  nothing useful (artist blank; title = the raw filename), and a match fills it
  with kanji/kana. query_page + pack_fields now surface the author's own romaji
  parsed from the filename ("Junko Yagami — BAY CITY") when the pack has no
  artist of its own — display-only, keyset-safe (raw title stashed for the
  cursor), a real pack artist or a user override still wins.
- Smart adopt: "Use these values" now KEEPS the readable romaji name + title the
  card already shows and takes only album/year/genre (+ art via the pin) from the
  match, so identifying a Japanese song gives "Junko Yagami — BAY CITY — FULL MOON"
  with the right cover, never native script.

Tests: romaji fallback fires for a blank-artist CDLC pack (grid + pack_fields
agree) and is left alone when the pack has a real artist.

server.py

@@ -1266,6 +1266,18 @@ class MetadataDB:
                 out.setdefault(fn, {})[field] = {"value": value, "locked": bool(locked)}
         return out
 
+    def _romaji_display(self, filename: str, artist: str, title: str):
+        """English-base display fallback. A blank-artist CDLC pack named
+        'Artist_Title_v1_p' has no readable name (artist blank; title = the raw
+        filename), and a match would fill it with the artist's NATIVE script
+        (kanji/kana). Surface the author's own romaji parsed from the filename
+        instead, so an English base reads 'Junko Yagami - BAY CITY'. Only kicks in
+        when the pack has no artist of its own — a real pack artist is untouched."""
+        if (artist or "").strip():
+            return artist, title
+        d = _artist_title_from_filename(filename)
+        return (d["artist"], d["title"]) if d else (artist, title)
+
     def pack_fields(self, filename: str) -> dict:
         """The stored (pack) values for the overridable catalog fields — the
         Fix-metadata popup shows these behind each override as the 'revert to
@@ -1275,7 +1287,11 @@ class MetadataDB:
         row = self.conn.execute(
             "SELECT title, artist, album, year, genre FROM songs WHERE filename = ?",
             (filename,)).fetchone()
-        return {k: ((row[i] or "") if row else "") for i, k in enumerate(keys)}
+        vals = {k: ((row[i] or "") if row else "") for i, k in enumerate(keys)}
+        # Baseline the author's romaji (from the filename) for a blank-artist pack,
+        # so the Details tab's Pack reference matches what the grid shows.
+        vals["artist"], vals["title"] = self._romaji_display(filename, vals["artist"], vals["title"])
+        return vals
 
     # Effective genre = a per-song genre OVERRIDE (Fix-metadata popup) else the
     # scanned pack genre. Applied at FILTER/FACET time (like the P4 artist alias)
@@ -4215,6 +4231,17 @@ class MetadataDB:
             s["unmatched"] = s["filename"] in um
             if amap:
                 s["artist"] = amap.get((s.get("artist") or "").lower(), s.get("artist"))
+            # English-base romaji fallback: a blank-artist CDLC pack shows nothing
+            # useful (artist blank; title = the raw filename). Surface the author's
+            # romaji from the "Artist_Title_v1_p" filename so the card reads
+            # "Junko Yagami — BAY CITY", never blank or native script. Display-only;
+            # a user override (below) still wins. Keyset-safe: stash the raw title
+            # for the cursor before replacing it.
+            if not (s.get("artist") or "").strip():
+                r_artist, r_title = self._romaji_display(s["filename"], s.get("artist"), s.get("title"))
+                if r_title != s.get("title") and "_sort_title" not in s:
+                    s["_sort_title"] = s["title"]
+                s["artist"], s["title"] = r_artist, r_title
             # Override wins over the pack AND the alias re-label — it's the user's
             # explicit per-song choice. Only a non-empty override VALUE replaces a
             # cell; a lock-only row (value None) leaves the displayed value alone.
@@ -4224,7 +4251,7 @@ class MetadataDB:
                     cell = ov.get(field)
                     val = cell.get("value") if cell else None
                     if val:
-                        if field == "title":
+                        if field == "title" and "_sort_title" not in s:
                             s["_sort_title"] = s["title"]   # raw title, for the keyset cursor
                         s[field] = val
         # Grouped rows carry the ⚑ N (chart_count) + the work_key from the

static/v3/match-review.js

@@ -511,10 +511,17 @@
     // then land on Details pre-filled for review.
     async function useTheseValues(song, cand) {
         if (!cand) return;
+        // Smart adopt for an English base: KEEP the readable name + title the card
+        // already shows (the author's romaji, e.g. "Junko Yagami / BAY CITY") — the
+        // match is often native script (kanji/kana). Take only what the pack lacks
+        // — album / year / genre — from the match; the pin below still brings the
+        // correct art + identity. The user can still edit any field.
         song._pendingDetails = {
-            title: String(cand.title || ''), artist: String(cand.artist || ''),
-            album: String(cand.album || ''), year: String(cand.year || ''),
-            genre: (Array.isArray(cand.genres) && cand.genres[0]) ? String(cand.genres[0]) : String(cand.genre || ''),
+            artist: String(song.artist || cand.artist || ''),
+            title:  String(song.title  || cand.title  || ''),
+            album:  String(cand.album  || song.album  || ''),
+            year:   String(cand.year   || song.year   || ''),
+            genre:  String((Array.isArray(cand.genres) && cand.genres[0]) || cand.genre || ''),
         };
         try {
             await post('/api/enrichment/review/' + enc(song.filename) + '/pick', { candidate: cand });

tests/test_field_overrides.py

@@ -233,6 +233,24 @@ def test_lock_only_genre_does_not_change_facet(server):
     assert server.meta_db._effective_genre_expr() == "genre"
 
 
+def test_romaji_fallback_for_blank_artist_pack(server):
+    fn = "CDLC/0 - City Pop/Junko-Yagami_BAY-CITY_v1_p.feedpak"
+    _put(server, fn, title="Junko-Yagami_BAY-CITY_v1_p", artist="")   # scanner fell back to the filename
+    s = {x["filename"]: x for x in server.meta_db.query_page()[0]}[fn]
+    # the grid shows the author's romaji, not blank / the raw filename / kanji
+    assert s["artist"] == "Junko Yagami"
+    assert s["title"] == "BAY CITY"
+    # the Details baseline (pack_fields) matches, so the popup agrees with the grid
+    pack = server.meta_db.pack_fields(fn)
+    assert pack["artist"] == "Junko Yagami" and pack["title"] == "BAY CITY"
+
+
+def test_romaji_fallback_left_alone_when_pack_has_artist(server):
+    _put(server, "a.archive", title="Real Title", artist="Real Artist")
+    s = {x["filename"]: x for x in server.meta_db.query_page()[0]}["a.archive"]
+    assert s["artist"] == "Real Artist" and s["title"] == "Real Title"
+
+
 def test_title_keyset_paging_is_complete_with_overrides(client, server):
     # Raw titles A/B/C → title-sort order is A, B, C on the RAW column.
     _put(server, "b.archive", title="B")