Enhanced quarterly confirmation system with approval workflow and export improvements

Features added:
- ✅ Fixed quarterly confirmation approval system with URL pattern
- ✅ Added re-approval and status reset functionality for quarterly confirmations
- ✅ Synchronized quarterly approval status with support payment system
- ✅ Enhanced Destinataer export with missing fields (anrede, titel, mobil)
- ✅ Added quarterly confirmation data and documents to export system
- ✅ Fixed address field display issues in destinataer template
- ✅ Added quarterly statistics dashboard to support payment lists
- ✅ Implemented duplicate support payment prevention and cleanup
- ✅ Added visual indicators for quarterly-linked support payments

Technical improvements:
- Enhanced create_quarterly_support_payment() with duplicate detection
- Added get_related_support_payment() method to VierteljahresNachweis model
- Improved quarterly confirmation workflow with proper status transitions
- Added computed address property to Destinataer model
- Fixed template field mismatches (anrede, titel, mobil vs strasse, plz, ort)
- Enhanced backup system with operation tracking and cancellation

Workflow enhancements:
- Quarterly confirmations now properly sync with support payments
- Single support payment per destinataer per quarter (no duplicates)
- Approval button works for both eingereicht and geprueft status
- Reset functionality allows workflow restart
- Export includes complete quarterly data with uploaded documents

paperless/Dockerfile

@@ -1,22 +0,0 @@
-# Custom Paperless-ngx with German OCR support
-FROM ghcr.io/paperless-ngx/paperless-ngx:latest
-
-# Switch to root to install packages
-USER root
-
-# Update package list and install German OCR language data
-# The correct package name is tesseract-ocr-deu (not tesseract-data-deu)
-RUN apt-get update && \
-    apt-get install -y \
-    tesseract-ocr-deu \
-    && apt-get clean && \
-    rm -rf /var/lib/apt/lists/*
-
-# Verify German language pack is installed
-RUN tesseract --list-langs | grep deu || echo "German language pack not found"
-
-# Switch back to paperless user
-USER paperless
-
-# Set the OCR language to include German and English
-ENV PAPERLESS_OCR_LANGUAGE=deu+eng