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>

src/lib/stores/settings.ts

@@ -8,6 +8,8 @@ export interface AppSettings {
   openai_model: string;
   anthropic_model: string;
   litellm_model: string;
+  litellm_api_key: string;
+  litellm_api_base: string;
   local_model_path: string;
   local_binary_path: string;
   transcription_model: string;
@@ -15,6 +17,7 @@ export interface AppSettings {
   transcription_language: string;
   skip_diarization: boolean;
   hf_token: string;
+  num_speakers: number | null;
 }
 
 const defaults: AppSettings = {
@@ -24,6 +27,8 @@ const defaults: AppSettings = {
   openai_model: 'gpt-4o-mini',
   anthropic_model: 'claude-sonnet-4-6',
   litellm_model: 'gpt-4o-mini',
+  litellm_api_key: '',
+  litellm_api_base: '',
   local_model_path: '',
   local_binary_path: 'llama-server',
   transcription_model: 'base',
@@ -31,6 +36,7 @@ const defaults: AppSettings = {
   transcription_language: '',
   skip_diarization: false,
   hf_token: '',
+  num_speakers: null,
 };
 
 export const settings = writable<AppSettings>({ ...defaults });
@@ -47,4 +53,20 @@ export async function loadSettings(): Promise<void> {
 export async function saveSettings(s: AppSettings): Promise<void> {
   settings.set(s);
   await invoke('save_settings', { settings: s });
+
+  // Configure the AI provider in the Python sidecar
+  const configMap: Record<string, Record<string, string>> = {
+    openai: { api_key: s.openai_api_key, model: s.openai_model },
+    anthropic: { api_key: s.anthropic_api_key, model: s.anthropic_model },
+    litellm: { api_key: s.litellm_api_key, api_base: s.litellm_api_base, model: s.litellm_model },
+    local: { model: s.local_model_path, base_url: 'http://localhost:8080' },
+  };
+  const config = configMap[s.ai_provider];
+  if (config) {
+    try {
+      await invoke('ai_configure', { provider: s.ai_provider, config });
+    } catch {
+      // Sidecar may not be running yet — provider will be configured on first use
+    }
+  }
 }