Adds the complete "KI verstehen" presentation (36 slides), the
Präsentations-Konfigurator (config.html + slides-manifest.js) for
curating which slides to show, and updates DESIGN.md/PATTERNS.md/
deck-template.html to reflect the new house font (General Sans) and
newly established patterns (chapter dividers, term tooltips, the
mitmach game, ambient sound, and the slide configurator).
