Expand deck to 42 slides, add speaker notes, and fix editor artifacts

Adds Grounding, Reasoning-Modelle, Token/Parameter examples, an
autocomplete mini-game, and a Copilot agent-building walkthrough with
a live chat-demo payoff. Adds Sprecher.md with per-slide speaker
cards. Fixes malformed data-def attributes and stray baked-in
active/visible classes left over from in-browser edit-mode sessions,
and stops the local save-in-place backups from being tracked.

.gitignore

@@ -1 +1,3 @@
 .DS_Store
+ki-verstehen.backup-*.html
+ki-verstehen-bearbeitet.html