[RNE Rewrite] fix(ts): release native resources when a create<Task> fails

[msluszniak]

Description

Fixes the finding recorded in #1355: a create<Task> that throws part-way through construction abandoned everything it had already allocated.

A factory allocates as it goes, and only hands back a dispose at the very end. Anything that threw in between left the caller with no reference to what was already there, and native memory is not garbage collected, so it stayed alive for the rest of the process. Depending on the task that is a model, a tokenizer, a phonemizer, an LLM runner, or a whole nested pipeline (Whisper owns both a tokenizer and a VAD). useModel re-runs its factory whenever the config changes, so an app pointed at a mismatched model leaked a full resource set per attempt.

src/core/lifetime.ts adds createResourceScope, which gives a factory one teardown path for both outcomes: it tracks each resource as it is created, releases them in reverse order, and the same function becomes the pipeline's dispose. Every factory now allocates through a scope and wraps its body in try/catch:

const scope = createResourceScope();
const dispose = scope.dispose;

try {
  const model = scope.track(await wrapAsync(loadModel, runtime)(modelPath));
  const { dims } = validateSpec(model.schema, { ... }); // may throw
  const tensors = [tensor('float32', outShape)] as const;
  tensors.forEach(scope.track);
  return { classify, classifyWorklet, dispose };
} catch (error) {
  dispose();
  throw error;
}

createKokoroTextToSpeech already did this with a local array and moves to the shared helper. That also closes a smaller hole it had: its two models were loaded before the try block, so one load rejecting stranded the other. Parallel loads elsewhere now track inside each promise for the same reason.

createTokenizer is unchanged. It loads a tokenizer and returns with nothing in between that can throw, so it has no window to leak through.

The helper is internal, so the public export surface is unchanged.

Introduces a breaking change?

• Yes
• No

Type of change

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Documentation update (improves or adds clarity to existing documentation)
• Other (chores, tests, code style improvements etc.)

Tested on

• iOS
• Android

Testing instructions

yarn workspace react-native-executorch test
yarn typecheck
yarn lint

Expected: 28 suites, 3117 tests, 4 snapshots, 0 skipped; typecheck and lint clean.

To see the tests bite, stash src/ and re-run: every construction-failure case fails.

Screenshots

N/A

Related issues

Follows up the finding recorded in #1355.

Checklist

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have updated the documentation accordingly
• My changes generate no new warnings

Additional notes

Stacked on @ms/api-tests (#1355), because that is where the suite recording this behavior lives. Merge #1355 first and this retargets to rne-rewrite cleanly.

tasks/constructionFailure.test.ts was written to record the leak as current behavior so it would fail loudly the day a factory started cleaning up. That is this PR, so it now asserts the opposite, and covers all fifteen factories rather than five. It checks every kind of handle, so a failure names the factory and the resource rather than just reporting that something leaked.

The per-pipeline suites and hooks/taskHooks.test.ts drop the allowNativeLeaks() calls they needed for the same reason. Nothing in the suite leaks any more, so the setup file's global leak check now asserts this on every construction-failure test for free.

The diff is large mostly because indenting a factory body inside try touches every line of it. The behavioral change per file is the scope, the track calls and the catch.

[barhanc]

Just a style comment. Otherwise looks solid.