Require login to create events when auth is enabled

Gate the home page and POST /events behind auth. Also add sqlite3 CLI
to the Docker image for DB inspection, and gitignore test.db files.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

handlers.go

@@ -49,6 +49,10 @@ func randomSlug() string {
 // --- Home / Create Event ---
 
 func (s *Server) handleHome(w http.ResponseWriter, r *http.Request) {
+	if s.features.Auth && s.currentUser(r) == nil {
+		http.Redirect(w, r, "/login", http.StatusSeeOther)
+		return
+	}
 	pageTmpl["home"].ExecuteTemplate(w, "layout", map[string]any{
 		"User":        s.currentUser(r),
 		"AuthEnabled": s.features.Auth,