fix: converge album cue extraction — weak-cue lowercase limited to one token, multi-word lowercase only after a strong cue, digit titles capture full continuation (closes task/album-cue-lower-run-converge)

Source: task/album-cue-lower-run-converge (plan/steward-linker-design) — the 16d8f74 LOWER_RUN both leaked lowercase prose and truncated digit-led titles; this converges the precision/recall balance.

- Weak cue (album|record|ep|lp): admit a capital/digit-led run OR a SINGLE lowercase token only (LOWER_ONE, guarded by a negative lookahead so a second lowercase word reads as prose and is rejected) — closes the 'makes me cry' / 'changed everything' prose leak.
- Strong cue (called|titled|named): the ONLY place a multi-word lowercase run (LOWER_RUN) is admitted — 'an album called good kid maad city' → 'good kid maad city'.
- New DIGIT_RUN (digit lead absorbs trailing lowercase tokens, bounded 1-4 words, tried before TITLE_RUN) fixes the digit truncation — '36 chambers'/'1989 deluxe'/'808s and heartbreak' capture in full.
- Position-mapping invariant enforced in the album push helper; bounded regexes (ReDoS test on a multi-KB pathological input); comprehensive BOTH-direction tests (precision: non-stop-set lowercase leads emit nothing; recall: digit continuation, single token, strong cue).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

extension/extract.test.cjs

@@ -112,10 +112,12 @@ test("albumMatchesIn: recall — number-led titles via an explicit album cue", (
   assert.ok(albumMatchesIn("the album 36 Chambers").map((m) => m.name).includes("36 Chambers"));
 });
 
-test("albumMatchesIn: recall — lowercase-styled titles after a cue", () => {
-  // good kid maad city is fully lowercase — a stylized title, not prose; the cue admits it.
+test("albumMatchesIn: recall — a lowercase-styled MULTI-word title needs a STRONG cue", () => {
+  // good kid maad city is fully lowercase. The WEAK cue (album|record|ep|lp) can't tell a stylized
+  // title from prose, so it emits NOTHING; a STRONG explicit cue (called|titled|named) licenses it.
+  assert.equal(albumMatchesIn("the album good kid maad city").length, 0); // weak cue → nothing
   assert.ok(
-    albumMatchesIn("the album good kid maad city").map((m) => m.name).includes("good kid maad city")
+    albumMatchesIn("an album called good kid maad city").map((m) => m.name).includes("good kid maad city")
   );
 });
 
@@ -173,6 +175,93 @@ test("albumMatchesIn: every rebalance candidate maps back to the source text", (
   }
 });
 
+// --- Convergence: the prior LOWER_RUN both leaked lowercase prose and truncated digit-led titles.
+// The stable design: weak cue (album|record|ep|lp) admits a capital/digit-led run OR a SINGLE
+// lowercase token only; a MULTI-word lowercase title needs a STRONG cue (called|titled|named); a
+// digit lead absorbs its full lowercase continuation. These assert BOTH directions — the precision
+// floor (album path emits NOTHING on non-stop-set lowercase leads, the bug the old test missed) AND
+// the recovered recall (digit continuation, single-token, strong-cue). ---
+
+test("albumMatchesIn: precision — weak-cue lowercase leads OUTSIDE the stop-set emit nothing", () => {
+  // The shipped leak: LOWER_RUN was guarded only by a 6-word stop-set, so any OTHER lowercase lead
+  // ('changed', 'dropped', 'makes', 'really', 'sounds') after a weak cue leaked a prose fragment.
+  for (const text of [
+    "the album i bought yesterday",
+    "this record changed everything for me",
+    "their ep dropped on bandcamp last night",
+    "the album makes me cry",
+    "the album really grew on me",
+    "the album sounds great",
+  ]) {
+    assert.equal(albumMatchesIn(text).length, 0, `expected no album candidate from: ${text}`);
+  }
+  // The old stop-set precision cases must still hold too.
+  assert.equal(albumMatchesIn("the album by Carcass").length, 0); // verb/article left edge
+  assert.equal(albumMatchesIn("I think their new LP is amazing").length, 0); // lowercase filler before LP
+  assert.equal(albumMatchesIn('"We hold these truths to be self-evident."').length, 0); // prose quote
+});
+
+test("albumMatchesIn: recall — a digit-led title captures its full lowercase continuation", () => {
+  // The shipped bug: TITLE_RUN's [A-Z0-9] lead matched the bare digit and stopped, so '36 chambers'
+  // truncated to '36'. The digit-led run now absorbs trailing lowercase tokens (bounded to 4 words).
+  assert.ok(albumMatchesIn("the album 36 chambers").map((m) => m.name).includes("36 chambers"));
+  assert.ok(albumMatchesIn("the album 1989 deluxe").map((m) => m.name).includes("1989 deluxe"));
+  assert.ok(
+    albumMatchesIn("the album 808s and heartbreak").map((m) => m.name).includes("808s and heartbreak")
+  );
+  // Prior digit recall cases (bare number, "X LP", capital-led mixed) still pass.
+  assert.ok(albumMatchesIn("the album 1989").map((m) => m.name).includes("1989"));
+  assert.ok(albumMatchesIn("1989 LP").map((m) => m.name).includes("1989"));
+  assert.ok(albumMatchesIn("the album 36 Chambers").map((m) => m.name).includes("36 Chambers"));
+});
+
+test("albumMatchesIn: recall — weak cue admits a SINGLE lowercase token (whole-title only)", () => {
+  // 'untitled' is the entire title — a lone lowercase token survives; a second lowercase word would
+  // be prose and is rejected (covered by the precision test above).
+  assert.ok(albumMatchesIn("the album untitled").map((m) => m.name).includes("untitled"));
+  assert.ok(albumMatchesIn("the album untitled.").map((m) => m.name).includes("untitled"));
+});
+
+test("albumMatchesIn: recall — a MULTI-word lowercase title needs a STRONG cue (called/titled/named)", () => {
+  // The ONLY place a bare multi-word lowercase run is admitted: an explicit naming verb.
+  assert.ok(
+    albumMatchesIn("an album called good kid maad city").map((m) => m.name).includes("good kid maad city")
+  );
+  assert.ok(albumMatchesIn("the record titled good kid maad city").map((m) => m.name).includes("good kid maad city"));
+  assert.ok(albumMatchesIn("the album named good kid maad city").map((m) => m.name).includes("good kid maad city"));
+  // The same multi-word lowercase run WITHOUT a strong cue emits nothing (the precision invariant).
+  assert.equal(albumMatchesIn("the album good kid maad city").length, 0);
+});
+
+test("albumMatchesIn: convergence cases all map back to the source text", () => {
+  // Position-mapping invariant across the new precision/recall cases (digit continuation, single
+  // token, strong cue) — text.substr(index, length) === name.
+  const texts = [
+    "the album 36 chambers",
+    "the album 1989 deluxe",
+    "the album 808s and heartbreak",
+    "the album untitled",
+    "the album untitled.",
+    "an album called good kid maad city",
+    "the record titled good kid maad city",
+    "the album Reign in Blood", // capital-led unchanged
+    "Reign in Blood LP",
+    "the album Money Store dropped",
+  ];
+  for (const text of texts) {
+    for (const m of albumMatchesIn(text)) assert.equal(text.substr(m.index, m.length), m.name);
+  }
+});
+
+test("albumMatchesIn: no ReDoS — a pathological multi-KB input returns promptly", () => {
+  // Bounded runs ({0,3}, single linear lookahead) must stay linear. A worst-case repeat of the
+  // cue + many tokens must not blow up; assert it completes well under a generous wall-clock bound.
+  const evil = "the album " + "a ".repeat(20000) + "!".repeat(20000);
+  const t0 = Date.now();
+  albumMatchesIn(evil);
+  assert.ok(Date.now() - t0 < 1000, "albumMatchesIn took too long on a pathological input");
+});
+
 test("isSafeHttpUrl accepts http/https and rejects javascript/data/garbage/empty", () => {
   // accepted: the only schemes a resolver link may inject as an href
   assert.ok(isSafeHttpUrl("https://open.spotify.com/artist/abc"));