- make dev serves all courses on port 1312 with marp live reload
- make dev-b/dev-c for single course on 1313/1314
- dev-kill only kills specific ports instead of all marp processes
- add generate-root-index.sh for prod build overview page
- cleanup function uses exec + trap instead of pid files
- simplify development: single marp server on port 3000 instead of 3 processes
- rename klausur to klausurfolien for better naming
- update extract script to use 00-intro.md as template when no 01-*.md exists
- update makefile and package.json for new workflow
- add comprehensive AGENTS.md guidelines
