fix(ci): restore npm ci with proper cross-platform lockfile

Previous lockfile was generated with --package-lock-only which skips
resolving platform-specific optional deps. Regenerated with full
npm install to include @biomejs/cli-linux-x64 entries.

Restored npm ci + cache in CI workflows (matching react-hotkey-display).

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

Author: mulkatz