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>

test/app.test.js

@@ -0,0 +1,16 @@
+const request = require('supertest');
+const app = require('../index');
+
+describe('TicTacToe App', () => {
+  it('GET / returns HTML', async () => {
+    const res = await request(app).get('/');
+    expect(res.statusCode).toBe(200);
+    expect(res.headers['content-type']).toMatch(/html/);
+  });
+
+  it('GET /health returns OK', async () => {
+    const res = await request(app).get('/health');
+    expect(res.statusCode).toBe(200);
+    expect(res.text).toBe('OK');
+  });
+});