Cross-platform distribution, UI improvements, and performance optimizations

- PyInstaller frozen sidecar: spec file, build script, and ffmpeg path resolver
  for self-contained distribution without Python prerequisites
- Dual-mode sidecar launcher: frozen binary (production) with dev mode fallback
- Parallel transcription + diarization pipeline (~30-40% faster)
- GPU auto-detection for diarization (CUDA when available)
- Async run_pipeline command for real-time progress event delivery
- Web Audio API backend for instant playback and seeking
- OpenAI-compatible provider replacing LiteLLM client-side routing
- Cross-platform RAM detection (Linux/macOS/Windows)
- Settings: speaker count hint, token reveal toggles, dark dropdown styling
- Loading splash screen, flexbox layout fix for viewport overflow
- Gitea Actions CI/CD pipeline (Linux, Windows, macOS ARM)
- Updated README and CLAUDE.md documentation

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

python/voice_to_notes.spec

@@ -0,0 +1,67 @@
+# -*- mode: python ; coding: utf-8 -*-
+"""PyInstaller spec for the Voice to Notes sidecar binary."""
+
+from PyInstaller.utils.hooks import collect_all
+
+block_cipher = None
+
+# Collect all files for packages that have shared libraries / data files
+# PyInstaller often misses these for ML packages
+ctranslate2_datas, ctranslate2_binaries, ctranslate2_hiddenimports = collect_all("ctranslate2")
+faster_whisper_datas, faster_whisper_binaries, faster_whisper_hiddenimports = collect_all(
+    "faster_whisper"
+)
+pyannote_datas, pyannote_binaries, pyannote_hiddenimports = collect_all("pyannote")
+
+a = Analysis(
+    ["voice_to_notes/main.py"],
+    pathex=[],
+    binaries=ctranslate2_binaries + faster_whisper_binaries + pyannote_binaries,
+    datas=ctranslate2_datas + faster_whisper_datas + pyannote_datas,
+    hiddenimports=[
+        "torch",
+        "torchaudio",
+        "huggingface_hub",
+        "pysubs2",
+        "openai",
+        "anthropic",
+        "litellm",
+    ]
+    + ctranslate2_hiddenimports
+    + faster_whisper_hiddenimports
+    + pyannote_hiddenimports,
+    hookspath=[],
+    hooksconfig={},
+    runtime_hooks=[],
+    excludes=["tkinter", "test", "unittest", "pip", "setuptools"],
+    win_no_prefer_redirects=False,
+    win_private_assemblies=False,
+    cipher=block_cipher,
+    noarchive=False,
+)
+
+pyz = PYZ(a.pure, a.zipped_data, cipher=block_cipher)
+
+exe = EXE(
+    pyz,
+    a.scripts,
+    [],
+    exclude_binaries=True,
+    name="voice-to-notes-sidecar",
+    debug=False,
+    bootloader_ignore_signals=False,
+    strip=False,
+    upx=True,
+    console=True,
+)
+
+coll = COLLECT(
+    exe,
+    a.binaries,
+    a.zipfiles,
+    a.datas,
+    strip=False,
+    upx=True,
+    upx_exclude=[],
+    name="voice-to-notes-sidecar",
+)