[NathanWalker]

Summary

Adds ns metadata trim, which reduces native API metadata to what an app's emitted JavaScript uses, plus the types those APIs depend on.

ns metadata trim <platform> <bundle...>
  collect declared rules (native-api-usage.json, --keep)
  toolchain.analyze    bundle + kept rules -> filter patterns (the runtime's own analyzers)
  stop if usage can't be bounded (dynamic global access, eval)
  toolchain.generate   patterns -> metadata (Apple; Gradle does this on Android)
  toolchain.install    embed into NativeScript.framework, or write whitelist.mdg

It builds on metadata filtering rather than replacing it: native-api-usage.json rules from the app and its plugins are merged with what the analysis finds.

The command is host-neutral. It takes a bundle path, so it doesn't assume a NativeScript project layout. Scope, how it works and how other hosts adopt it are in the RFC: NativeScript/rfcs#62.

lib/
├── commands/metadata-trim.ts
├── definitions/metadata-trim-service.d.ts   # IMetadataToolchain, the extension point
└── services/
    ├── metadata-trim-service.ts             # analyze -> generate -> install
    └── metadata-trim/
        ├── apple-toolchain.ts               # ns-metadata-symbols + objc-metadata-generator
        ├── android-toolchain.ts             # the runtime's seed.js, then Gradle
        ├── declared-rules.ts                # merges native-api-usage.json rules
        └── macho-metadata.ts                # replaces and shrinks __objc_metadata

Related fix on the generator: NativeScript/runtimes@cb26a2b.

Evidence

Run on a TSX app embedding NativeScript in nsh: macOS 26, iOS 26.5 simulator, Android 16 emulator. Not yet run on physical devices or against a standard ns project.

	macOS	iOS	Android
Before: metadata	4.7 MB	4.6 MB	2.9 MB
After: metadata	0.67 MB	0.83 MB	0.81 MB
Before: framework, compressed	2.36 MB	1.84 MB	n/a
After: framework, compressed	0.95 MB	0.84 MB	n/a

• A native-view check (creation, layout, both directions of a signal binding, unmount and remount) passes 7/7 on all three platforms running on trimmed metadata.
• npx vitest run: 2167 passed, 9 skipped, including new tests for the Mach-O rewrite and both toolchains.
• A bundle with dynamic global access stops with "Nothing was trimmed" and generates nothing.
• native-api-usage.json on a project fixture: the app's whitelist and blacklist and a plugin's uses all reach the generator, and whitelist-plugins-usages: false drops the plugin's entry.
• Android through Gradle: a uses entry adds WebView and a blacklist entry removes Build.VERSION. Blacklisting a type a kept API needs fails the build and names it.

Merge Danger

Door: two-way

Additive. It introduces one new command, with its options scoped to that command. Nothing calls it from prepare or build.

Blast Radius: additive

Only people who run the new command are affected. A trimmed app that reaches an API the analysis can't see fails at run time in that code path, which is why this is opt-in and the RFC covers the rollout.

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