fix(player): redesign cleanup pass — sleeve, tonearm, AGC, dead code

Production-readiness pass before merging the Studio Reference redesign
to master.

Audio (backend):
- Reset AGC `_spectrum_ref` envelope on `start()` so a long silent gap
  between sessions doesn't make the first new transients clip at the
  ceiling. Annotated the trade-off (loud transient lifts reference for
  a few seconds afterwards — the price of real loudness).
- Add `tests/test_audio_analyzer.py` with 10 cases: bin-edge layout,
  AGC attack/release asymmetry, lifecycle reset. Skips numpy-dependent
  cases when numpy isn't installed; CI has it.

Vinyl mode dead code removed:
- The toggle button was dropped during the sleeve refactor but the JS
  state, 2 s `setInterval`, `beforeunload` handler, and `applyVinylMode`
  call (commented out in app.js) all stayed. Now properly excised from
  player.js + app.js + window.* exports.
- Stripped the matching `.album-art-container.vinyl*` CSS block and its
  `vinylSpin` keyframes (~95 LoC).

Sleeve + tonearm fixes:
- Removed the duplicate `.now-playing .vinyl-stage` / `.vinyl-label` /
  `.tonearm` block that was overriding the new `.vinyl-stage` rules by
  source order — the uncommitted tonearm geometry never took effect
  because the stale clone won the cascade.
- Tightened tonearm to 36% × 36% at right:-6%, top:26% so the SVG
  bounding box stays right of the sleeve (sleeve right edge ~68%).
  Needle now lands on the visible disc grooves at both rest and
  playing rotations and never overlaps the cover.
- Removed sleeve `transform: rotate(-2.5deg)` + the matching mobile
  `-1.8deg` override; sleeve now sits flat and squared-off.
- Removed the 1px inset hairline on the sleeve and the 1px outline +
  inset highlight on the album art — cleaner, no semitransparent
  border noise.
- Album art inset 5% to expose a cardstock margin around the print
  (using explicit width/height — `inset` shorthand triggered the CSS
  replaced-element rule that uses the image's intrinsic size and blew
  out the grid track).

Mobile + misc:
- Removed mobile tonearm overrides at 720px and 420px — they were
  calibrated for the pre-sleeve geometry and put the needle back over
  the cover on phones; desktop geometry is proportional and works.
- Added `<meta name="mobile-web-app-capable">` alongside the legacy
  Apple variant to silence the deprecation warning in Chromium.
- Replaced the "PRIMARY" badge on display cards with a copper star
  icon (translation key still drives title + aria-label).
- `.gitattributes` with `* text=auto eol=lf` so Windows checkouts stop
  nagging "LF will be replaced by CRLF".

Annotations:
- "REF · 24" record-label catalogue mark marked as intentional non-i18n
  decoration in index.html.

CI: ruff clean, pytest 7 passed + 3 numpy-skipped (all 10 run on CI).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/test_audio_analyzer.py

@@ -0,0 +1,152 @@
+"""Tests for AudioAnalyzer.
+
+Covers the pure-Python pieces that don't need real audio hardware:
+- Logarithmic FFT bin edge layout
+- Slow-AGC envelope follower (attack vs release behaviour)
+- Lifecycle reset of the AGC reference on start()
+
+Tests are skipped when numpy isn't installed in the host environment
+so they don't block CI on a minimal interpreter.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from media_server.services.audio_analyzer import AudioAnalyzer, _load_numpy
+
+np = _load_numpy()
+needs_numpy = pytest.mark.skipif(np is None, reason="numpy not available")
+
+
+@pytest.fixture
+def analyzer() -> AudioAnalyzer:
+    return AudioAnalyzer(num_bins=16, sample_rate=44100, chunk_size=1024)
+
+
+# ── _compute_bin_edges ────────────────────────────────────────────
+
+
+@needs_numpy
+def test_bin_edges_count_matches_num_bins_plus_one(analyzer: AudioAnalyzer) -> None:
+    edges = analyzer._compute_bin_edges()
+    assert len(edges) == analyzer.num_bins + 1
+
+
+@needs_numpy
+def test_bin_edges_are_monotonic_non_decreasing(analyzer: AudioAnalyzer) -> None:
+    edges = analyzer._compute_bin_edges()
+    assert all(edges[i] <= edges[i + 1] for i in range(len(edges) - 1))
+
+
+@needs_numpy
+def test_bin_edges_stay_within_fft_size(analyzer: AudioAnalyzer) -> None:
+    edges = analyzer._compute_bin_edges()
+    fft_size = analyzer.chunk_size // 2 + 1
+    assert max(edges) <= fft_size - 1
+    assert min(edges) >= 0
+
+
+# ── AGC envelope follower (the new behaviour) ─────────────────────
+
+
+def _step_envelope(analyzer: AudioAnalyzer, peak: float) -> float:
+    """Run one frame of the AGC update with a known peak value.
+
+    Mirrors the math inside _capture_loop without spinning up a real
+    capture thread or requiring numpy: pure Python on a single float.
+    """
+    if peak > analyzer._spectrum_ref:
+        analyzer._spectrum_ref += (peak - analyzer._spectrum_ref) * 0.05
+    else:
+        analyzer._spectrum_ref += (peak - analyzer._spectrum_ref) * 0.005
+    return analyzer._spectrum_ref
+
+
+def test_agc_initial_reference_is_quiet(analyzer: AudioAnalyzer) -> None:
+    assert analyzer._spectrum_ref == pytest.approx(0.01)
+
+
+def test_agc_attacks_quickly_toward_loud_signal(analyzer: AudioAnalyzer) -> None:
+    # Drive 30 frames of a loud signal; reference should climb sharply.
+    for _ in range(30):
+        _step_envelope(analyzer, peak=1.0)
+    # 30 frames of attack=0.05 brings (1 - 0.99^30) ≈ 0.78 of the way to 1.0.
+    assert analyzer._spectrum_ref > 0.5
+    assert analyzer._spectrum_ref < 1.0
+
+
+def test_agc_releases_slowly_toward_quiet_signal(analyzer: AudioAnalyzer) -> None:
+    analyzer._spectrum_ref = 1.0
+    for _ in range(30):
+        _step_envelope(analyzer, peak=0.0)
+    # Release coefficient is 0.005 — after 30 frames we should have shed
+    # only ~14% of the headroom, not snap back to silent.
+    assert analyzer._spectrum_ref > 0.7
+    assert analyzer._spectrum_ref < 1.0
+
+
+def test_agc_is_asymmetric_attack_faster_than_release(analyzer: AudioAnalyzer) -> None:
+    a = AudioAnalyzer()
+    b = AudioAnalyzer()
+    a._spectrum_ref = 0.5
+    b._spectrum_ref = 0.5
+    # One attack frame toward 1.0
+    _step_envelope(a, peak=1.0)
+    # One release frame toward 0.0 (same magnitude of error: 0.5)
+    _step_envelope(b, peak=0.0)
+    attack_delta = a._spectrum_ref - 0.5
+    release_delta = 0.5 - b._spectrum_ref
+    # Attack coefficient (0.05) is 10× the release coefficient (0.005).
+    assert attack_delta == pytest.approx(release_delta * 10, rel=1e-6)
+
+
+# ── start() lifecycle reset ──────────────────────────────────────
+
+
+def test_start_resets_spectrum_ref_when_unavailable(
+    monkeypatch: pytest.MonkeyPatch, analyzer: AudioAnalyzer
+) -> None:
+    """Even when start() returns False (no hardware), the AGC state
+    should remain at the documented quiet baseline."""
+    # Force unavailable so start() short-circuits without spawning a thread.
+    monkeypatch.setattr(
+        AudioAnalyzer, "available", property(lambda self: False)
+    )
+    analyzer._spectrum_ref = 0.95  # leftover from prior session
+    started = analyzer.start()
+    assert started is False
+    # start() returned early before the reset — by design (no capture
+    # means no need to renormalize). Document the contract.
+    assert analyzer._spectrum_ref == 0.95
+
+
+def test_start_resets_spectrum_ref_when_available(
+    monkeypatch: pytest.MonkeyPatch, analyzer: AudioAnalyzer
+) -> None:
+    """When capture actually starts, leftover AGC state from a prior
+    session must be cleared so the first transients don't clip."""
+    monkeypatch.setattr(
+        AudioAnalyzer, "available", property(lambda self: True)
+    )
+    # Stub out the thread so we don't actually spin up a capture loop.
+    monkeypatch.setattr(
+        "media_server.services.audio_analyzer.threading.Thread",
+        lambda *a, **kw: type("T", (), {"start": lambda self: None})(),
+    )
+    analyzer._spectrum_ref = 0.95  # leftover from prior session
+    try:
+        started = analyzer.start()
+        assert started is True
+        assert analyzer._spectrum_ref == pytest.approx(0.01)
+    finally:
+        analyzer._running = False
+
+
+# ── get_frequency_data thread-safe contract ───────────────────────
+
+
+def test_get_frequency_data_returns_none_before_capture(
+    analyzer: AudioAnalyzer,
+) -> None:
+    assert analyzer.get_frequency_data() is None