feat: launch readiness — PWA, API hardening, memory leak fixes, sticker removal

- Add PWA infrastructure: vite-plugin-pwa, manifest, service worker,
  SW update prompt component, placeholder icons, Apple meta tags
- Harden API client: 401 auto-logout, AbortController timeouts
  (30s standard, 120s uploads), onUnauthorized callback
- Fix memory leaks: clear voice user status on leave, clean up all
  Maps (channelToSpaceMap, permissions, etc.) on removeSpace
- Upgrade error boundary to Aether Drift design with Try Again button,
  collapsible stack trace, and componentDidCatch logging
- Configure desktop icon paths in electron-builder.yml
- Remove sticker feature (server routes, schema, types, UI components)
- Fix Docker build: use **/node_modules in .dockerignore to prevent
  COPY from clobbering pnpm-installed workspace dependencies
- Add vite-env.d.ts declarations for noise suppressor wasm imports
- Exclude test files from tsc build via tsconfig

.dockerignore

@@ -1,4 +1,4 @@
-node_modules
+**/node_modules
 .git
 .gitignore
 .env