sync: features from private repo (2025-12-24)

Synced from ra-h private repo:
- Collapsible chat panel (Cmd+\)
- FolderViewOverlay with Kanban/Grid/List views
- Updated agent prompts
- Improved executor and quickAdd services
- New views.ts types

Files kept at OS versions (auth/backend deps):
- SettingsModal, RAHChat, useSSEChat
- Delegation tools and wiseRAHExecutor
- openExternalUrl (no Tauri)

Added stub: supabaseTokenRegistry.ts for compatibility

src/services/context/supabaseTokenRegistry.ts

@@ -0,0 +1,22 @@
+/**
+ * Stub for SupabaseTokenRegistry - not used in open source version
+ * The private version uses this for backend API authentication.
+ * In open source mode, all API calls go directly to OpenAI/Anthropic.
+ */
+export class SupabaseTokenRegistry {
+  static async get(_key: string): Promise<string | null> {
+    return null;
+  }
+  
+  static getLast(_key: string): string | null {
+    return null;
+  }
+  
+  static set(_key: string, _value: string): void {
+    // No-op in OS version
+  }
+  
+  static delete(_key: string): void {
+    // No-op in OS version
+  }
+}