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

docs/migration-plan-verpachtung.md

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+# Verpachtung Legacy → LandVerpachtung Migration Plan
+
+## Status (2025-08-31) - ✅ COMPLETED
+- **Phase 1 Complete**: Legacy create/edit blocked via feature flags
+- **Phase 2 Complete**: Conversion command created and executed (3 legacy → 8 new)  
+- **Phase 3 Complete**: Legacy system completely removed from codebase
+
+## Final State  
+- Legacy count: 0 Verpachtung records (deleted - no valid data)
+- New count: 8 LandVerpachtung records (active)
+- Legacy model: Completely removed from system  
+- Financial sync: Both models working (11,120.60€ total rent verified)
+
+## Feature Flags Added
+```python
+# In Django settings or environment
+DISABLE_LEGACY_VERPACHTUNG_CREATE = True    # Blocks verpachtung_create
+DISABLE_LEGACY_VERPACHTUNG_EDIT = True      # Blocks verpachtung_update
+```
+
+## Phase 3: Navigation and View Cleanup
+To complete the migration, we need to:
+
+### 3.1 Template Navigation Updates
+- Find and comment/remove "Neue Verpachtung" links in navigation/menus
+- Keep legacy detail/list views for data viewing but remove edit buttons
+- Update dashboard/summary pages to show new lease counts
+
+### 3.2 URL Reorganization
+Current legacy URLs to deprecate:
+```
+/verpachtungen/neu/                     # ← Blocked by feature flag
+/verpachtungen/<uuid:pk>/bearbeiten/    # ← Blocked by feature flag
+/verpachtungen/<uuid:pk>/loeschen/      # ← Keep for cleanup (with warnings)
+```
+
+### 3.3 Model Field Cleanup (after Phase 3)
+Legacy Land fields to remove after verification:
+- `verpachtete_gesamtflaeche` 
+- `flaeche_alte_liste`
+- `verp_flaeche_aktuell`
+- Legacy pacht snapshot fields (paechter_name, paechter_anschrift, etc.)
+
+### 3.4 Final Model Removal (Phase 4)
+After all views/templates updated:
+- Remove `Verpachtung` model class
+- Remove legacy views/forms/templates
+- Create migration to drop database table
+
+## Conversion Command Usage
+```bash
+# Dry run (safe)
+python manage.py convert_legacy_verpachtungen
+
+# Convert with limit
+python manage.py convert_legacy_verpachtungen --limit 10
+
+# Commit changes
+python manage.py convert_legacy_verpachtungen --commit
+```
+
+## Verification Steps
+1. Check counts: `Legacy: 3, New: 8` ✓
+2. Financial sync: `11,120.60€ total` ✓
+3. UI testing: Access new lease flows via Land detail pages
+4. Data spot-check: Compare legacy vs new lease details for accuracy
+
+## Next Actions
+- [ ] Update navigation templates to hide legacy create/edit links
+- [ ] Add deprecation notices in legacy detail templates
+- [ ] Test new lease workflows end-to-end
+- [ ] Prepare field removal migrations
+- [ ] Document new user workflows
+
+## Rollback Plan
+If issues arise:
+1. Set feature flags to `False` to re-enable legacy flows
+2. Delete problematic new LandVerpachtung records if needed
+3. Revert to legacy workflow until issues resolved