fix: clear lyrics-review cache on job status change

renderLyricsReview was caching its job ID only in the done path, allowing
stale data to persist when switching between done/running/failed jobs.
Now clears the cache in the failed and not-done branches so a previously-
viewed done job always re-fetches when re-selected.

Regression test: test_lyrics_review_cache_clears_on_job_status_change
verifies both branches clear the cache key before rendering placeholders.

src/songtrace/static/index.html

@@ -872,10 +872,12 @@ function buildLyricsReview(data) {
 async function renderLyricsReview(job) {
   const box = document.getElementById("lyrics-review");
   if (job.status === "failed") {
+    delete box.dataset.jobId;
     box.replaceChildren(emptyNote("job failed — nothing to review"));
     return;
   }
   if (job.status !== "done") {
+    delete box.dataset.jobId;
     box.replaceChildren(emptyNote("waiting for this song to finish…"));
     return;
   }

tests/test_web.py

@@ -433,6 +433,23 @@ def test_index_lyrics_review_uses_endash_for_time_ranges():
     assert "–" in body
 
 
+def test_lyrics_review_cache_clears_on_job_status_change():
+    """Regression: switching between done/failed/running jobs must clear the
+    cache so a previously-viewed done job re-fetches when re-selected."""
+    html = _index_html()
+    body = _fn_body(html, "renderLyricsReview")
+    # The "failed" branch must clear the cache before rendering the placeholder
+    assert re.search(
+        r'if\s*\(\s*job\.status\s*===\s*"failed"\s*\)\s*\{[^}]*'
+        r'delete\s+box\.dataset\.jobId',
+        body, re.S), "failed branch must delete cache key"
+    # The "not done" (queued/running) branch must clear the cache before rendering
+    assert re.search(
+        r'if\s*\(\s*job\.status\s*!==\s*"done"\s*\)\s*\{[^}]*'
+        r'delete\s+box\.dataset\.jobId',
+        body, re.S), "not done branch must delete cache key"
+
+
 def test_index_has_copy_path_control():
     assert "copy-path" in _index_html()