fix(docker): resolve @cc-platform/server file: dep in container build

Use additional_contexts to copy platform server package into the Docker
build context. Rewrites the file: dependency path and removes the
lockfile so npm install can resolve the local package correctly.
Applied to both production and dev Dockerfiles.

server/Dockerfile.dev

@@ -3,12 +3,20 @@ FROM node:18-alpine
 
 WORKDIR /app
 
+# Copy platform server package from additional build context
+COPY --from=platform-server . /app/platform-server/
+RUN rm -rf /app/platform-server/node_modules
+
 # Install nodemon for hot reload
 RUN npm install -g nodemon
 
 # Copy package files
 COPY package*.json ./
 
+# Rewrite file: dependency to use the local copy inside the container
+RUN sed -i 's|file:../../cc-platform-core/server|file:./platform-server|' package.json \
+    && rm -f package-lock.json
+
 # Install all dependencies (including dev)
 RUN npm install