Add dockerfile and workflow

Dockerfile

@@ -0,0 +1,28 @@
+# syntax=docker/dockerfile:1
+
+# ---- Build stage: compile the Vite/SolidJS app to static files ----
+FROM node:24-alpine AS build
+WORKDIR /app
+
+# pnpm ships with Node via corepack; pin to the version that produced pnpm-lock.yaml.
+RUN corepack enable && corepack prepare pnpm@10.33.0 --activate
+
+# Install deps first so this layer is cached unless the manifest/lockfile change.
+COPY package.json pnpm-lock.yaml ./
+RUN pnpm install --frozen-lockfile
+
+# Build (`tsc && vite build` → /app/dist). devDependencies are needed here.
+COPY . .
+RUN pnpm build
+
+# ---- Serve stage: static files via `serve` ----
+FROM node:24-alpine AS serve
+WORKDIR /app
+
+# `serve` (what `npx serve` runs) — installed at build time so the image is self-contained.
+RUN npm install -g serve@14
+
+COPY --from=build /app/dist ./dist
+
+EXPOSE 3000
+CMD ["serve", "-s", "dist", "-l", "3000"]