feat: Add complete Verpachtung management system

- Add LandVerpachtung model with Land and Paechter relationships
- Implement full CRUD operations for Verpachtungen
- Add responsive Bootstrap templates with JavaScript calculations
- Integrate document linking functionality similar to other entities
- Add navigation links and URL patterns
- Include CSV import support for Paechter data
- Fix template encoding issues for proper UTF-8 support
- Enhance administration interface with Verpachtung CSV import

This implements the complete Verpachtung management feature requested,
allowing users to manage land lease agreements with proper relationships
to properties (Laenderei) and tenants (Paechter), following the same
patterns as Foerderung/Destinataer relationships.

compose.yml

@@ -1,3 +1,11 @@
+# Production Docker Compose Configuration
+# This file is used for production deployment via GitHub Actions
+# For local development, use: docker-compose -f compose.dev.yml up
+# 
+# IMPORTANT: This configuration requires ALL environment variables to be 
+# provided via the production server's .env file. No fallback values are 
+# included for security reasons.
+
 services:
   db:
     image: postgres:16-alpine
@@ -8,7 +16,7 @@ services:
     volumes:
       - dbdata:/var/lib/postgresql/data
     healthcheck:
-      test: ["CMD-SHELL", "pg_isready -U $$POSTGRES_USER -d $$POSTGRES_DB"]
+      test: ["CMD-SHELL", "pg_isready -U $${POSTGRES_USER} -d $${POSTGRES_DB}"]
       interval: 10s
       timeout: 5s
       retries: 5
@@ -23,7 +31,20 @@ services:
         condition: service_healthy
       redis:
         condition: service_started
-    env_file: ./app/.env
+    environment:
+      - POSTGRES_DB=${POSTGRES_DB}
+      - POSTGRES_USER=${POSTGRES_USER}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
+      - DB_HOST=${DB_HOST}
+      - DB_PORT=${DB_PORT}
+      - DJANGO_SECRET_KEY=${DJANGO_SECRET_KEY}
+      - DJANGO_DEBUG=${DJANGO_DEBUG}
+      - DJANGO_ALLOWED_HOSTS=${DJANGO_ALLOWED_HOSTS}
+      - LANGUAGE_CODE=${LANGUAGE_CODE}
+      - TIME_ZONE=${TIME_ZONE}
+      - REDIS_URL=${REDIS_URL}
+      - PAPERLESS_API_URL=${PAPERLESS_API_URL}
+      - PAPERLESS_API_TOKEN=${PAPERLESS_API_TOKEN}
     ports:
       - "8081:8000"
     volumes:
@@ -32,7 +53,15 @@ services:
 
   worker:
     build: ./app
-    env_file: ./app/.env
+    environment:
+      - POSTGRES_DB=${POSTGRES_DB}
+      - POSTGRES_USER=${POSTGRES_USER}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
+      - DB_HOST=${DB_HOST}
+      - DB_PORT=${DB_PORT}
+      - DJANGO_SECRET_KEY=${DJANGO_SECRET_KEY}
+      - DJANGO_DEBUG=${DJANGO_DEBUG}
+      - REDIS_URL=${REDIS_URL}
     depends_on:
       - redis
       - db
@@ -40,7 +69,15 @@ services:
 
   beat:
     build: ./app
-    env_file: ./app/.env
+    environment:
+      - POSTGRES_DB=${POSTGRES_DB}
+      - POSTGRES_USER=${POSTGRES_USER}
+      - POSTGRES_PASSWORD=${POSTGRES_PASSWORD}
+      - DB_HOST=${DB_HOST}
+      - DB_PORT=${DB_PORT}
+      - DJANGO_SECRET_KEY=${DJANGO_SECRET_KEY}
+      - DJANGO_DEBUG=${DJANGO_DEBUG}
+      - REDIS_URL=${REDIS_URL}
     depends_on:
       - redis
       - db
@@ -76,9 +113,9 @@ services:
       - PAPERLESS_STATIC_URL=/paperless/static/
       - PAPERLESS_LOGIN_REDIRECT_URL=/paperless/
       - PAPERLESS_LOGOUT_REDIRECT_URL=/paperless/
-      - PAPERLESS_ADMIN_USER=${PAPERLESS_ADMIN_USER:-admin}
-      - PAPERLESS_ADMIN_PASSWORD=${PAPERLESS_ADMIN_PASSWORD:-admin123}
-      - PAPERLESS_ADMIN_MAIL=${PAPERLESS_ADMIN_MAIL:-admin@vhtv-stiftung.de}
+      - PAPERLESS_ADMIN_USER=${PAPERLESS_ADMIN_USER}
+      - PAPERLESS_ADMIN_PASSWORD=${PAPERLESS_ADMIN_PASSWORD}
+      - PAPERLESS_ADMIN_MAIL=${PAPERLESS_ADMIN_MAIL}
     volumes:
       - paperless_data:/usr/src/paperless/data
       - paperless_media:/usr/src/paperless/media