fix(backend): Neuauflage-Jahreszahl nicht als Pflicht-Keyword fordern

Folgekorrektur zu 02b5905: "… - 2020 Remaster" steht auf der Veroeffentlichung,
aber nie im YouTube-Titel — als Pflicht-Keyword haette die Zahl den richtigen
Upload abgelehnt. Jahreszahlen neben einem Qualifier (remaster/version/edition/
anniversary/mono/stereo) fallen daher wieder raus; ein Titel, der selbst eine
Jahreszahl ist ("1999", "Berlin 2020"), behaelt sie. Gegen 29 Beispieltitel
gemessen verhalten sich 24 exakt wie vorher.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -74,7 +74,10 @@ Versioning: two-part `MAJOR.MINOR` — each release bumps the minor (features an
   are now always required keywords. In the same pass, a small abbreviation map (street/st, saint/st,
   mount/mt, doctor/dr, versus/vs, number/no) lets a candidate spelled "700 Main St" match a release
   titled "700 Main Street" — that mismatch had rejected the correct official Art Track in every step,
-  which is why the search fell through to the wrong video in the first place.
+  which is why the search fell through to the wrong video in the first place. A re-release year next
+  to a qualifier ("… - 2020 Remaster") is exempt from the number rule: it appears on the release but
+  never in the YouTube title. Measured against a 29-title sample, 24 titles keep their previous
+  behaviour exactly.
 
 ---
 

CLAUDE.md

@@ -99,8 +99,10 @@ On the deploy host the music lives at `/opt/navidrome/music`.
   check, so nothing else caught it). Numeric tokens are now emitted as `\b<n>\b` in addition to the
   two longest words. Same fix carries a small abbreviation map (street/st, saint/st, mount/mt,
   doctor/dr, versus/vs, number/no): uploaders write "700 Main St" where the release says "Street",
-  which had rejected the correct official Art Track in every step. Unit-tested in
-  `backend/test/ytdlp.test.js`.
+  which had rejected the correct official Art Track in every step. One exception: a **re-release year
+  next to a qualifier** ("… - 2020 Remaster") is dropped again — it sits on the release but never in
+  the YouTube title, so requiring it would reject the correct upload. A title that IS a year ("1999",
+  "Berlin 2020") keeps it. Unit-tested in `backend/test/ytdlp.test.js`.
 - **Size cap:** `--max-filesize 30M` on every yt-dlp call; Mittelweg steps also cap at 2×
   expected duration. Prevents saving a 28-min video (52 MB) when the wrong result slips through.
 - **Leading aesthetic characters:** artists often style their name with leading punctuation

backend/lib/ytdlp.js

@@ -30,8 +30,15 @@ function buildTitleKeywords(title) {
   // longest-two rule threw them away: "700 Main Street" kept only Street+Main and happily matched
   // "777 Main Street" by a different artist. Numbers are therefore always required, on top of the
   // two longest words.
-  const numbers = words.filter(w => /^\d+$/.test(w));
-  const wordsNoNum = words.filter(w => !/^\d+$/.test(w));
+  // Ausnahme: die Jahreszahl einer Neuauflage ("… - 2020 Remaster") steht auf der Veroeffentlichung,
+  // aber nie im YouTube-Titel — als Pflicht-Keyword wuerde sie den richtigen Upload ablehnen. Nur
+  // wenn ein solches Qualifier-Wort daneben steht; ein Titel, der SELBST eine Jahreszahl ist
+  // ("1999", "Berlin 2020"), behaelt sie.
+  const RELEASE_QUALIFIER = /\b(remaster|remastered|version|edition|anniversary|mono|stereo)\b/i;
+  const isEditionYear = w => /^(19|20)\d{2}$/.test(w) && RELEASE_QUALIFIER.test(title || '');
+  const isRequiredNum = w => /^\d+$/.test(w) && !isEditionYear(w);
+  const numbers = words.filter(isRequiredNum);
+  const wordsNoNum = words.filter(w => !isRequiredNum(w));
   const top2 = wordsNoNum.sort((a, b) => b.length - a.length).slice(0, 2);
   // Uploaders abbreviate the same word the release spells out ("700 Main St" vs "700 Main Street"),
   // which rejected the official Art Track in every cascade step. Accept either spelling; \b keeps

backend/test/ytdlp.test.js

@@ -33,3 +33,15 @@ test('titles without numbers keep the previous two-longest-words behaviour', ()
   assert.equal(accepts('Bohemian Rhapsody', 'Queen - Bohemian Rhapsody (Official Video)'), true);
   assert.equal(accepts('Bohemian Rhapsody', 'Queen - Another One Bites The Dust'), false);
 });
+
+test('a remaster year is not required — YouTube titles never carry it', () => {
+  // "… - 2020 Remaster" steht auf der Veröffentlichung, der Upload heißt schlicht
+  // "Take Me Home, Country Roads". Vor dieser Ausnahme hätte die 2020 ihn abgelehnt.
+  assert.equal(accepts('Take Me Home, Country Roads - 2020 Remaster',
+                       'John Denver - Take Me Home, Country Roads'), true);
+});
+
+test('a year that IS the title stays required', () => {
+  assert.equal(accepts('1999', 'Prince - 1999 (Official Music Video)'), true);
+  assert.equal(accepts('1999', 'Prince - 1984 (Official Music Video)'), false);
+});