feat: initial tictactoe web app with CI/CD pipeline

- Express app serving vanilla JS 2-player TicTacToe game
- Dockerfile (multi-stage node:18-slim)
- Jenkinsfile (K8s pod: test → Harbor push → Helm bump → Gitea push)
- Helm chart v1.0.0 with HTTPRoute for tictactoe.fireflylab.local

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

index.js

@@ -0,0 +1,18 @@
+const express = require('express');
+const path = require('path');
+const app = express();
+const port = process.env.PORT || 3000;
+
+app.use(express.static(path.join(__dirname, 'public')));
+
+app.get('/health', (req, res) => {
+  res.status(200).send('OK');
+});
+
+if (require.main === module) {
+  app.listen(port, () => {
+    console.log(`TicTacToe running on port ${port}`);
+  });
+}
+
+module.exports = app;