fix(tests): re-green the JS suite — 18 stale source-shape tests + 1 real seek-reason violation (#740)

main's JS suite has been red since the recent v3-library and player
refactors landed. 17 of 18 failures were test harnesses/regexes that
went stale behind real, intentional code changes; one was a genuine
contract violation in the code.

Code fix:
- session-resume seek passed 'resume' as its _audioSeek reason; the
  documented contract (enforced by song_seek.test.js) requires
  multi-word kebab-case. Renamed to 'session-resume' — no consumer
  string-matches specific reasons, so this is rename-safe.

Test updates (each pins the CURRENT contract):
- highway_colors_facade: inject HWC_PRESETS + applyHighwayStringPreset
  (new preset feature); lock presets/applyPreset into the surface test
- loop_api: stub _updateEditRegionBtn (new edit-region UI hook)
- song_close: sandbox gets window.feedBack.playQueue; assert a real
  close abandons the queue (the new queue-aware behavior)
- v3_keep_practicing: the shelf moved from client-side /api/stats/recent
  dedupe+gating to the server-side practice-suggestions recommender —
  tests now pin that (fetch, arrangement-aware card click, Promise.all)
- v3_songs_tuning: card row variable renamed song → shown (grouped cards)
- live_guitar_tone_source: accept literal ’ where ’ drifted in copy
- legacy_shim_hits: normalize CRLF before fixed-width region() slicing
  (Windows-only failure; char windows shrank by one char per line)

Suite: 987/987 locally (Windows), previously 968/987 (and 18 red on CI).

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

static/app.js

@@ -6195,7 +6195,7 @@ window.feedBack.on('song:ready', () => {
             setSpeed(pend.speed);
         }
     } catch (_) { /* speed restore is best-effort */ }
-    Promise.resolve(_audioSeek(Math.max(0, Number(pend.position) || 0), 'resume'))
+    Promise.resolve(_audioSeek(Math.max(0, Number(pend.position) || 0), 'session-resume'))
         .then(() => { if (_autoplayExitEnabled() && !isPlaying) return togglePlay(); })
         .catch((err) => console.warn('[app] resume failed:', err));
 });