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>

Dockerfile

@@ -0,0 +1,17 @@
+# Build stage
+FROM node:18-slim AS builder
+WORKDIR /app
+COPY package*.json ./
+RUN npm install --production
+COPY . .
+
+# Production stage
+FROM node:18-slim
+WORKDIR /app
+COPY --from=builder /app/package*.json ./
+COPY --from=builder /app/node_modules ./node_modules
+COPY --from=builder /app/index.js ./
+COPY --from=builder /app/public ./public
+
+EXPOSE 3000
+CMD ["node", "index.js"]