feat(docker): add Dockerfile and .dockerignore for app containerization

Dockerfile

@@ -0,0 +1,63 @@
+# syntax=docker/dockerfile:1
+
+# ---- Base image with pnpm enabled ----
+FROM node:20-slim AS base
+WORKDIR /app
+ENV NEXT_TELEMETRY_DISABLED=1 \
+    PNPM_HOME=/usr/local/share/pnpm
+ENV PATH=${PNPM_HOME}:${PATH}
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends ca-certificates openssl \
+    && rm -rf /var/lib/apt/lists/* \
+    && corepack enable
+
+# ---- Install dependencies (cached layer) ----
+FROM base AS deps
+COPY package.json pnpm-lock.yaml ./
+RUN pnpm install --frozen-lockfile
+
+# ---- Build the Next.js application ----
+FROM base AS builder
+ARG DATABASE_URL="postgresql://postgres:postgres@localhost:5432/postgres"
+ARG NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=""
+ENV DATABASE_URL=${DATABASE_URL} \
+    NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=${NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY}
+COPY --from=deps /app/node_modules ./node_modules
+COPY . .
+RUN mkdir -p public
+RUN pnpm run prisma:generate
+RUN pnpm run build
+
+# ---- Prune devDependencies for the runtime image ----
+FROM deps AS prod-deps
+RUN pnpm prune --prod
+
+# ---- Production runtime ----
+FROM node:20-slim AS runner
+ARG NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=""
+WORKDIR /app
+ENV NODE_ENV=production \
+    NEXT_TELEMETRY_DISABLED=1 \
+    PORT=3000 \
+    NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY=${NEXT_PUBLIC_CLERK_PUBLISHABLE_KEY}
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends ca-certificates openssl \
+    && rm -rf /var/lib/apt/lists/* \
+    && mkdir -p /app \
+    && chown node:node /app
+
+# Copy only what is required to run `next start`
+COPY --from=prod-deps --chown=node:node /app/node_modules ./node_modules
+COPY --from=builder --chown=node:node /app/package.json ./package.json
+COPY --from=builder --chown=node:node /app/.next ./.next
+# Copy public assets only if they exist in the project
+COPY --from=builder --chown=node:node /app/public ./public
+COPY --from=builder --chown=node:node /app/next.config.js ./next.config.js
+
+# Keep the filesystem owned by the non-root user
+USER node
+
+EXPOSE 3000
+
+# `next start` will read any variables from the environment or a mounted .env.local
+CMD ["node", "./node_modules/next/dist/bin/next", "start"]