fix: rebuild when linked library changes

[biw]

Summary

• Hash local libraries resolved by linker flags as native build-cache inputs.
• Add regression coverage for a changed -L / -l static library.
• Document the behavior and release swift-node and swift-node-unplugin as 1.0.1.

Testing

• pnpm exec vp check
• pnpm --dir packages/swift-node exec vp test run test/build-cache.test.ts
• node scripts/check-package-versions.mjs --baseline-ref origin/main