✨ feat(calendar): add complete calendar app with backend, web, and landing

- NestJS backend with Drizzle ORM (port 3014)
  - Calendar, Event, Reminder, Share, Sync modules
  - Full CRUD API endpoints
  - PostgreSQL database schema (5 tables)

- SvelteKit web app with Svelte 5 runes (port 5179)
  - Week, Day, Month views
  - Agenda list view
  - Event management (create, edit, delete)
  - Calendar management
  - Auth integration with Mana Core Auth
  - i18n support (DE, EN, FR, ES, IT)

- Astro landing page (port 4322)
  - Hero, Features, Pricing sections
  - Responsive dark theme design

- @calendar/shared package
  - TypeScript types for Calendar, Event, Reminder, Share
  - RFC 5545 RRULE support for recurring events

- Full documentation (CLAUDE.md, README.md)

apps/calendar/README.md

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+# Kalender
+
+> Smart Calendar Management - Organisiere deine Zeit intelligent
+
+Eine vollständige Kalender-Anwendung mit persönlichen und geteilten Kalendern, wiederkehrenden Terminen, CalDAV/iCal-Synchronisation und Erinnerungen.
+
+## Features
+
+- **Mehrere Kalender** - Verwalte verschiedene Kalender für Arbeit, Privates, Familie
+- **Kalenderansichten** - Tag, Woche, Monat, Agenda
+- **Wiederkehrende Termine** - Flexible Wiederholungsregeln (RFC 5545)
+- **Kalender teilen** - Mit Familie, Freunden oder Kollegen
+- **CalDAV/iCal Sync** - Google Calendar, Apple, Outlook
+- **Smarte Erinnerungen** - Push & E-Mail Benachrichtigungen
+- **Multi-Sprache** - Deutsch, English, Français, Español, Italiano
+
+## Quick Start
+
+```bash
+# 1. PostgreSQL starten (falls nicht läuft)
+docker compose -f docker-compose.dev.yml up -d postgres
+
+# 2. Datenbank erstellen
+PGPASSWORD=devpassword psql -h localhost -U manacore -d postgres -c "CREATE DATABASE calendar;"
+
+# 3. Schema pushen
+pnpm calendar:db:push
+
+# 4. Backend + Web starten
+pnpm dev:calendar:app
+```
+
+## Apps
+
+| App | Port | Beschreibung |
+|-----|------|--------------|
+| [Backend](apps/backend) | 3014 | NestJS REST API |
+| [Web](apps/web) | 5179 | SvelteKit Web-App |
+| [Landing](apps/landing) | 4322 | Astro Marketing-Seite |
+| Mobile | - | Expo App (TODO) |
+
+## Tech Stack
+
+- **Backend**: NestJS, Drizzle ORM, PostgreSQL
+- **Web**: SvelteKit, Svelte 5, Tailwind CSS
+- **Landing**: Astro, Tailwind CSS
+- **Auth**: Mana Core Auth (JWT)
+
+## Dokumentation
+
+Siehe [CLAUDE.md](CLAUDE.md) für die vollständige technische Dokumentation.
+
+## Entwicklung
+
+```bash
+# Einzelne Apps starten
+pnpm dev:calendar:backend    # Backend
+pnpm dev:calendar:web        # Web-App
+pnpm dev:calendar:landing    # Landing Page
+
+# Datenbank
+pnpm calendar:db:push        # Schema pushen
+pnpm calendar:db:studio      # Drizzle Studio öffnen
+```
+
+## API Endpunkte
+
+| Modul | Endpunkt | Beschreibung |
+|-------|----------|--------------|
+| Health | `GET /api/v1/health` | Health Check |
+| Calendars | `GET/POST /api/v1/calendars` | Kalender CRUD |
+| Events | `GET/POST /api/v1/events` | Termine CRUD |
+| Reminders | `POST /api/v1/events/:id/reminders` | Erinnerungen |
+| Shares | `POST /api/v1/calendars/:id/shares` | Freigaben |
+| Sync | `POST /api/v1/sync/caldav/discover` | CalDAV |
+
+## Lizenz
+
+Proprietär - Manacore