Initial commit — 2048 terminal game

Plain TS + Vite, JetBrains Mono terminal aesthetic. Includes engine
(pure logic, direction normalization, tile tracking), animated UI
(CSS transitions + keyframes), keyboard/touch input, Dockerfile,
nginx config, docker-compose, and Gitea Actions CI workflow.

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

vite.config.ts

@@ -0,0 +1,6 @@
+import { defineConfig } from 'vite'
+
+export default defineConfig({
+  server: { port: 5678, strictPort: true },
+  preview: { port: 4588, strictPort: true },
+})