feat: 8 AI providers, rich text editor, agent notifications, UI contrast & font settings

- Add DeepSeek, OpenRouter, Mistral, Z.AI, LM Studio as AI providers
  with editable model names via Combobox in admin settings
- Fix OpenRouter broken by normalizeProvider bug in config.ts
- Convert agent-created notes from Markdown to HTML (TipTap rich text)
- Add Notification model + in-app notifications for agent results
- Agent notification click opens the created note directly
- Add note count display on notebook and inbox headers
- Fix checklist toggle in card view (persist state via localCheckItems)
- Add checklist creation option in tabs/list view (dropdown on + button)
- Fix image description ENOENT error with HTTP fallback
- Improve UI contrast across all themes (input, border, checkbox visibility)
- Add font family setting (Inter vs System Default) in Appearance settings
- Fix CSS font-sans variable conflict (removed dead Geist references)
- Update README with new features and 8 providers

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

memento-note/docker-compose.yml

@@ -38,6 +38,7 @@ services:
       # Application (IMPORTANT: Change these!)
       - NEXTAUTH_URL=http://your-domain.com:3000
       - NEXTAUTH_SECRET=change-this-to-a-random-secret-string
+      - ADMIN_EMAIL=admin@yourdomain.com  # REQUIRED: first user with this email gets ADMIN role
 
       # Disable Next.js telemetry
       - NEXT_TELEMETRY_DISABLED=1