Add swift-node native addon support

[biw]

Summary

Adds swift-node 0.1.0 loader support so its target-qualified native addons and runtime sidecars are emitted with valid runtime paths.

What This PR Does

• Recognizes swift-node 0.1.0's generated resolveAddonPath() loader
• Resolves macOS flat binaries plus Linux and Windows target subdirectories, including Linux musl targets
• Preserves Swift runtime .so and .dll sidecar filenames beside the hashed addon

What This Improves

• Bundles swift-node packages, including macos-native-clone-file

What This Does Not Do

• Does not execute a native Swift binary during the test suite

Important Context

• No configuration, migration, or release artifact changes

Code To Review Closely

src/index.ts:328

Verify that sidecars are emitted only for a resolved swift-node addon and retain the filenames required by the dynamic linker.

const sidecarPaths =
  process.platform === "darwin"
    ? []
    : fs
        .readdirSync(path.dirname(binaryPath))
        .filter((filename) =>
          process.platform === "win32"
            ? filename.toLowerCase().endsWith(".dll")
            : /\.so(?:\..+)?$/i.test(filename),
        )
        .map((filename) => path.join(path.dirname(binaryPath), filename));

return { nodeFilePath: binaryPath, sidecarPaths };

Gotchas, Risks, And Edge Cases

• Target selection uses the build host's platform, architecture, and Linux libc detection, matching swift-node 0.1.0
• Conflicting runtime-sidecar filenames with different contents fail the build

Tests And Regression Coverage

Validation Run

• pnpm test: 200 passing tests
• pnpm lint: formatting, lint, and type checks passed
• pnpm build: ESM and CommonJS package builds passed

Coverage Assessment

Sufficient for generated-loader bundling because the tests cover the 0.1.0 resolver, emitted hashed addon, and Linux/Windows sidecar assets.

Regressions These Tests Should Catch

• Unresolved resolveAddonPath() calls from swift-node 0.1.0
• Missing native assets for the macOS or target-subdirectory layouts
• Missing Swift runtime sidecars on Linux and Windows

Gaps And Recommended Follow-Up Tests

• Native runtime execution remains covered by the consuming package rather than this plugin's fake-addon fixture

Follow-Up Work

• Not applicable