docker: update dockerfile to use pnpm features

Dockerfile

@@ -1,15 +1,25 @@
-FROM node:18-bullseye-slim
+FROM node:20-bullseye-slim AS base
+ENV PNPM_HOME="/pnpm"
+ENV PATH="$PNPM_HOME:$PATH"
+
+FROM base AS build
+WORKDIR /app
+COPY . /app
+
+RUN corepack enable
+RUN apt-get update && \
+    apt-get install -y python3 build-essential
+
+RUN --mount=type=cache,id=pnpm,target=/pnpm/store \
+    pnpm install --prod --frozen-lockfile
+
+RUN pnpm deploy --filter=@imput/cobalt-api --prod /prod/api
+
+FROM base AS api
 WORKDIR /app
 
-COPY package*.json ./
+COPY --from=build /prod/api /app
+COPY --from=build /app/.git /app/.git
 
-RUN apt-get update                                    && \
-    apt-get install -y git python3 build-essential    && \
-    npm ci                                            && \
-    npm cache clean --force                           && \
-    apt purge --autoremove -y python3 build-essential && \
-    rm -rf ~/.cache/ /var/lib/apt/lists/*
-
-COPY . .
 EXPOSE 9000
-CMD [ "node", "src/cobalt" ]
+CMD [ "node", "src/cobalt" ]