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>

main.go

@@ -174,7 +174,11 @@ func main() {
 
 	// Home / create event
 	r.Get("/", srv.handleHome)
-	r.Post("/events", srv.handleCreateEvent)
+	if features.Auth {
+		r.With(srv.requireAuth).Post("/events", srv.handleCreateEvent)
+	} else {
+		r.Post("/events", srv.handleCreateEvent)
+	}
 
 	// Guest event view
 	r.Get("/e/{slug}", srv.handleEvent)