chore: .gitignore und features/ aus Git-Tracking entfernen (nur lokal)

Ignore-Regeln liegen jetzt in .git/info/exclude und werden
nie nach Gitea übertragen.

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

.gitignore

@@ -1,53 +0,0 @@
-# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
-
-# dependencies
-/node_modules
-/.pnp
-.pnp.js
-.yarn/install-state.gz
-
-# testing
-/coverage
-
-# next.js
-/.next/
-/out/
-
-# production
-/build
-
-# misc
-.DS_Store
-*.pem
-
-# debug
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-
-# local env files
-.env*.local
-
-# vercel
-.vercel
-
-# claude code – komplett ignorieren
-.claude/
-
-# AI Coding Starter Kit – Template-Docs
-docs/production/
-features/README.md
-
-# AI Coding Starter Kit – Supabase Template (nicht verwendet)
-src/lib/supabase.ts
-
-# Next.js Default-Assets (AI Coding Starter Kit)
-public/file.svg
-public/globe.svg
-public/next.svg
-public/vercel.svg
-public/window.svg
-
-# typescript
-*.tsbuildinfo
-next-env.d.ts