feat: playground static site with cursor webhook deploy

Scaffold nginx + deploy-hook stack for playground.schwenk.online,
Gitea cursor workflow, directory-based public/ content, and boka
bootstrap via git clone.

Co-authored-by: Cursor <cursoragent@cursor.com>

NOTES.md

@@ -0,0 +1,19 @@
+# NOTES.md
+
+Scratchpad for this repo.
+
+---
+
+## boka
+
+- Pfad `/home/frank/playground.schwenk.online` = Git-Clone von `froxxxy/playground`
+- Deploy: Push auf `main` → Webhook → `git pull` im Repo-Root
+- `.env` auf boka (nicht im Git): `WEBHOOK_SECRET`, `DEPLOY_GIT_TOKEN`, `HOST_UID`/`HOST_GID`
+
+**Offen (Fränky):**
+
+- [ ] Gitea: `cursor`-Bot als Collaborator
+- [ ] Gitea Secrets: `CURSOR_API_KEY`, `CURSOR_BOT_TOKEN`
+- [ ] Gitea Push-Webhook → `https://playground.schwenk.online/hooks/deploy`
+- [ ] `DEPLOY_GIT_TOKEN` in boka `.env` (falls Repo privat)
+- [ ] Smoke: `@cursor` in Test-Issue