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>

tests/js/loop_api.test.js

@@ -107,6 +107,7 @@ function loadFunctions(sandbox, src) {
             sectionPracticeModeCalls.push({ on, opts: opts || {} });
         }
         function _updateSectionPracticeHighlight(ct) {}
+        function _updateEditRegionBtn() {}
         ${extractFunction(src, 'function clearLoop(')}
         ${extractFunction(src, 'function _syncSavedLoopSelection()')}
         ${extractFunction(src, 'async function setLoop(')}