fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/.dockerignore

@@ -0,0 +1,70 @@
+# Virtual Environment
+venv/
+.venv/
+env/
+.env/
+
+# Python cache
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+
+# Distribution
+dist/
+build/
+*.egg-info/
+.eggs/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+*~
+
+# Testing
+.pytest_cache/
+.coverage
+htmlcov/
+.tox/
+
+# Local config
+.env
+.env.local
+*.local
+
+# Logs
+*.log
+logs/
+
+# Temp files
+*.tmp
+*.temp
+.DS_Store
+
+# Documentation builds
+docs/_build/
+
+# Backup files
+*.bak
+*.save
+*_backup.py
+*_before_*.py
+
+# Large files
+*.docx
+*.zip
+*.pdf
+
+# Git
+.git/
+.gitignore
+
+# Docker
+Dockerfile
+docker-compose*.yml
+
+# Secrets directory (conflicts with Python stdlib secrets module)
+secrets/