fix: configure CI database connection properly

- Add dotenv loading to Django settings
- Update CI workflow to use correct environment variables
- Set POSTGRES_* variables instead of DATABASE_URL
- Add environment variables to all Django management commands
- Fixes CI test failures due to database connection issues

app/stiftung/utils/config.py

@@ -0,0 +1,73 @@
+"""
+Configuration utilities for the Stiftung application
+"""
+from django.conf import settings
+from stiftung.models import AppConfiguration
+
+
+def get_config(key, default=None, fallback_to_settings=True):
+    """
+    Get a configuration value from the database or fall back to Django settings
+    
+    Args:
+        key: The configuration key
+        default: Default value if not found
+        fallback_to_settings: If True, try to get from Django settings using the key in uppercase
+    
+    Returns:
+        The configuration value
+    """
+    # Try to get from AppConfiguration first
+    value = AppConfiguration.get_setting(key, None)
+    
+    # Fall back to Django settings if value is None or empty string
+    if not value and fallback_to_settings:
+        settings_key = key.upper()
+        return getattr(settings, settings_key, default)
+    
+    return value if value is not None else default
+
+
+def get_paperless_config():
+    """
+    Get all Paperless-related configuration values
+    
+    Returns:
+        dict: Dictionary containing all Paperless configuration
+    """
+    return {
+        'api_url': get_config('paperless_api_url', 'http://192.168.178.167:30070'),
+        'api_token': get_config('paperless_api_token', ''),
+        'destinataere_tag': get_config('paperless_destinataere_tag', 'Stiftung_Destinatäre'),
+        'destinataere_tag_id': get_config('paperless_destinataere_tag_id', '210'),
+        'land_tag': get_config('paperless_land_tag', 'Stiftung_Land_und_Pächter'),
+        'land_tag_id': get_config('paperless_land_tag_id', '204'),
+        'admin_tag': get_config('paperless_admin_tag', 'Stiftung_Administration'),
+        'admin_tag_id': get_config('paperless_admin_tag_id', '216'),
+    }
+
+
+def set_config(key, value, **kwargs):
+    """
+    Set a configuration value
+    
+    Args:
+        key: The configuration key
+        value: The value to set
+        **kwargs: Additional parameters for AppConfiguration.set_setting
+    
+    Returns:
+        AppConfiguration: The configuration object
+    """
+    return AppConfiguration.set_setting(key, value, **kwargs)
+
+
+def is_paperless_configured():
+    """
+    Check if Paperless is properly configured
+    
+    Returns:
+        bool: True if API URL and token are configured
+    """
+    config = get_paperless_config()
+    return bool(config['api_url'] and config['api_token'])