fix(dockerfile): use pnpm exec prisma generate in production stage

pnpm does not hoist workspace package binaries to /app/node_modules/.bin;
each package's .bin/ is only available within that package's node_modules.
Use 'pnpm exec prisma generate' from the service directory so pnpm can
resolve the prisma binary from the local node_modules/.bin symlink.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Dockerfile.service

@@ -91,8 +91,9 @@ ARG SERVICE_NAME
 COPY --from=builder /app/packages/services/${SERVICE_NAME}/prisma packages/services/${SERVICE_NAME}/prisma/
 RUN if [ -f "packages/services/${SERVICE_NAME}/prisma/schema.prisma" ]; then \
       echo "Running prisma generate for ${SERVICE_NAME}..." && \
-      /app/node_modules/.bin/prisma generate \
-        --schema /app/packages/services/${SERVICE_NAME}/prisma/schema.prisma && \
+      cd packages/services/${SERVICE_NAME} && \
+      pnpm exec prisma generate --schema prisma/schema.prisma && \
+      cd /app && \
       echo "Prisma generate completed."; \
     else \
       echo "No prisma/schema.prisma found — skipping prisma generate."; \