feat: Add Nixpacks configuration for Node.js and pnpm build and start commands.

nixpacks.toml

@@ -0,0 +1,11 @@
+[phases.setup]
+nixPkgs = ["nodejs_22", "pnpm-9_x"]
+
+[phases.install]
+cmds = ["pnpm install --no-frozen-lockfile"]
+
+[phases.build]
+cmds = ["pnpm run build"]
+
+[start]
+cmd = "pnpm run start"