Migrate package manager from Yarn 3 to pnpm 10 #331

Context

The project currently uses Yarn 3.8.7 with Node.js 18.20 and the node-modules linker.

Before upgrading the Node.js runtime and refreshing frontend dependencies, migrate the project to pnpm while keeping the current runtime and dependency versions unchanged. This keeps the package-manager migration isolated from the later Node.js 24 and dependency upgrade work.

Scope

• Replace Yarn 3 with pnpm 10.
• Generate and commit pnpm-lock.yaml.
• Add the required pnpm workspace/configuration files.
• Preserve the existing workspace layout for resources/frontend/vendor_modules/*/*.
• Migrate the current Yarn-specific configuration:
  • npm scope/registry settings;
  • package extensions;
  • dependency resolution overrides where required.
• Update packageManager in package.json.
• Update Docker/build scripts and CI workflows to use pnpm.
• Remove Yarn-specific files and plugins that are no longer needed.
• Keep Node.js at 18.x for this change.
• Keep application dependency versions unchanged unless a minimal compatibility fix is required for pnpm.

Acceptance criteria

• pnpm install --frozen-lockfile succeeds on Node.js 18.
• pnpm prod produces a successful production frontend build.
• pnpm lint succeeds.
• Docker image build succeeds using pnpm.
• CI no longer depends on Yarn.
• No Yarn runtime/configuration artifacts remain unless explicitly required and documented.
• The migration does not intentionally change application behavior or upgrade the frontend dependency stack.

Non-goals

• Node.js 24 migration.
• pnpm 12 migration.
• Bulk dependency updates.
• Vue 2 → Vue 3 migration.
• Laravel Mix → Vite migration.

These should be handled separately after this migration is complete.