🔥 chore: remove maerchenzauber from codebase

- Remove app definition from MANA_APPS and APP_URLS
- Remove AppId type entry and branding config
- Delete app icon SVG and StorytellerLogo component
- Remove StorytellerLogo export from logos/index.ts and main index.ts
- Delete maerchenzauber.css theme file
- Delete landing page content (maerchenzauber-de.md)
- Remove env generation config for backend/mobile/web
- Update CLAUDE.md archived projects list

packages/shared-landing-ui/src/themes/maerchenzauber.css

@@ -1,24 +0,0 @@
-/**
- * Märchenzauber Theme - Golden/Yellow Dark Theme (Children's App)
- * Import this file in your landing page to use the Märchenzauber color scheme
- */
-:root {
-  /* Primary colors - Märchenzauber Gold */
-  --color-primary: #6D5B00;
-  --color-primary-hover: #F8D62B;
-  --color-primary-glow: rgba(248, 214, 43, 0.3);
-
-  /* Text colors */
-  --color-text-primary: #FFFFFF;
-  --color-text-secondary: #999999;
-  --color-text-muted: #666666;
-
-  /* Background colors */
-  --color-background-page: #181818;
-  --color-background-card: #2C2C2C;
-  --color-background-card-hover: #333333;
-
-  /* Border colors */
-  --color-border: #444444;
-  --color-border-hover: #555555;
-}