Revert "build: remove buildkit cache"

This reverts commit 2a17474.

Dockerfile

@@ -1,20 +1,19 @@
 FROM node:20-slim AS base
-
 ENV PNPM_HOME="/pnpm"
 ENV PATH="$PNPM_HOME:$PATH"
 RUN corepack enable
-
-FROM base AS prod
-
-COPY pnpm-lock.yaml /app
+COPY . /app
 WORKDIR /app
-RUN pnpm fetch --prod
 
-COPY . /app
+FROM base AS prod-deps
+RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --prod --frozen-lockfile
+
+FROM base AS build
+RUN --mount=type=cache,id=pnpm,target=/pnpm/store pnpm install --frozen-lockfile
 RUN pnpm run build
 
 FROM base
-COPY --from=prod /app/node_modules /app/node_modules
-COPY --from=prod /app/dist /app/dist
+COPY --from=prod-deps /app/node_modules /app/node_modules
+COPY --from=build /app/dist /app/dist
 
 CMD [ "pnpm", "start:docker" ]