Add CLAUDE.md, MkDocs docs, .claude/rules

- CLAUDE.md: Comprehensive documentation for Lehrer KI platform
- docs-src: Klausur, Voice, Agent-Core, KI-Pipeline docs
- mkdocs.yml: Lehrer-specific nav with blue theme
- docker-compose: Added docs service (port 8010, profile: docs)
- .claude/rules: testing, docs, open-source, abiturkorrektur, vocab-worksheet, multi-agent, experimental-dashboard

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

docs-src/index.md

@@ -0,0 +1,21 @@
+# BreakPilot Lehrer - Dokumentation
+
+Willkommen zur Dokumentation der **BreakPilot Lehrer KI-Plattform**.
+
+## Module
+
+- **Klausur-Service**: OCR, Korrektur, Vokabel-Worksheets
+- **Voice-Service**: Spracheingabe und Transkription
+- **Agent-Core**: Multi-Agent System
+- **KI-Daten-Pipeline**: Datenverarbeitung
+
+## Architektur
+
+- [Multi-Agent System](architecture/multi-agent.md)
+- [Zeugnis-System](architecture/zeugnis-system.md)
+
+## Entwicklung
+
+- [Testing](development/testing.md)
+- [Dokumentation](development/documentation.md)
+- [CI/CD Pipeline](development/ci-cd-pipeline.md)