Add Lotus Terminal Mode + fix all remaining Cinny branding

- New: Lotus Terminal Mode toggle in Appearance settings
  - Red phosphor color scheme (bg #0a0000, primary #ff3300, accent #00dd66)
  - Monospace font override (JetBrains Mono / Fira Code / Cascadia Code)
  - Retro CRT scanline overlay via CSS pseudo-element
  - Wired into ThemeManager with dedicated lotusTerminalBodyClass
- Branding: replace all user-visible Cinny references with Lotus Chat
  - WelcomePage, AuthLayout, SplashScreen, index.html meta tags
  - Device display names in login/register/token flows
  - System notification brand field
  - (Preserved internal Matrix protocol CinnySpaces event type)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/pages/auth/login/TokenLogin.tsx

@@ -57,7 +57,7 @@ export function TokenLogin({ token }: TokenLoginProps) {
     startLogin(baseUrl, {
       type: 'm.login.token',
       token,
-      initial_device_display_name: 'Cinny Web',
+      initial_device_display_name: 'Lotus Chat Web',
     });
   }, [baseUrl, token, startLogin]);