feat(ui): redesign voice cockpit with clinical companion drawer, Svelte 5 migration, and Gemini 3.8 voice

- Re-architect VoiceSession into full-bleed studio cockpit with overlay slide-over companion drawer
- Eliminate width squishing defect on LiveInsightPanel and add native dark/light theme support
- Integrate authentic Google Gemini 3.8 Flash TTS with Fenrir persona and fallback audio pipeline
- Implement comprehensive Playwright E2E visual regression suite across Desktop, iPad, and iPhone (21 tests, 45 snapshots)
- Migrate core application to Svelte 5 runes (, , ) with reactive stores
- Maintain .NET 8 Azure Functions serverless endpoints and clean build hygiene

types.ts

@@ -16,6 +16,23 @@ export interface UserSettings {
   vocalStyle: string;
   genderPreference: 'Male' | 'Female' | 'Neutral';
   preferredAudioDeviceId?: string;
+  openRouterApiKey?: string;
+  geminiApiKey?: string;
+  voiceEngine?: 'gemini' | 'openrouter';
+  roleplayModel?: string;
+  supervisorModel?: string;
+}
+
+export interface SavedSession {
+  id: string;
+  scenarioId: string;
+  scenarioTitle: string;
+  category: Scenario['category'];
+  difficulty: Scenario['difficulty'];
+  timestamp: string;
+  mode: SessionMode;
+  messages: Message[];
+  finalReport?: AnalysisResult;
 }
 
 export interface Message {