Add VitePress site with local login and deployment docs

Enable static site build on port 12100 with Express session auth, auto sidebar, and DEPLOY.md for Ubuntu/NPS setup.

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

server/auth.config.example.json

@@ -0,0 +1,5 @@
+{
+  "username": "admin",
+  "password": "change-me",
+  "sessionSecret": "please-change-this-session-secret"
+}