Regenerate pnpm-lock.yaml for RN 0.87 dependency bumps

Rebased onto main after the npm->pnpm migration (#381). The original PR's
two package-lock.json maintenance commits (restore public registry URLs,
restore pruned optional platform binaries) are dropped: both addressed
npm-specific lockfile problems that no longer exist under pnpm.

Regenerate pnpm-lock.yaml against the RN 0.87 nightly / react-native-test-app
5.x / @rnx-kit/metro-config bumps so the lockfile matches the workspace
manifests. Verified with pnpm install --frozen-lockfile.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TVfanKvtyfSsoMgZv3DJtY

Author: claude