fix(hub): fold case/whitespace in album grouping, flatten loose tracks

- groupMusicEntries: artist/album grouping keys are now case- and
  whitespace-folded ("Racing With The Sun" vs "Racing with the sun" —
  a single mistagged track split a real album into two cards, reported
  live). The first spelling seen stays the display string; nothing is
  rewritten. Validated against a real ~5700-file library: 22 distinct
  (artist, album) pairs had more than one raw spelling before this,
  including the reported Chinese Man case.
- The untagged-tracks bucket per artist gets a dedicated, non-foldable
  key rather than folding the translated placeholder text, so it stays
  one bucket regardless of UI language, and sorts after every real
  album rather than wherever the placeholder's spelling lands
  alphabetically.
- Flat mode: an artist folder whose only "album" is that untagged
  bucket — a real, common shape here, a pile of loose singles with no
  album layer at all — no longer nests them behind an always-empty
  "Unknown album" row to expand first. They render directly under the
  artist. onPlayQueue already builds its queue from the whole bucket
  regardless of nesting, so previous/next already spanned the full
  pile; this only removes the pointless extra click to reach it.

Client-side only, no protocol/index change — a page reload picks it
up, no node restart needed. `npm run sync-ui` re-run. Full suite: 1129
passed, no regressions (JS structural checks — test_hook_ordering.py,
test_transport_contracts.py — included).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KBi7ALLGfwcjBXt57yNMcy

1 files changed, 0 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/music-app.js b/packages/meshbay-hub/src/meshbay_hub/static/music-app.js
index 85f1938..b170e97 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/music-app.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/music-app.js