feat(core): native update scheduler and commit hook (phase 0) - #11414

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What is the current behavior?

A property setter is the native call. Each Property/CssProperty/CssAnimationProperty/InheritedCssProperty setter carries its own copy of the "suspended → record in _suspendedUpdates, else [setNative](value)" block (six copies). The first native pass happens at onLoaded in the order properties were first set on that instance; afterwards every set is one synchronous native call. There is no way for a widget to see "these properties changed together", no previous committed value, no public batching primitive (_batchUpdate is private and per node), and no way for a flavor to coalesce writes across nodes.

What is the new behavior?

Phase 0 of the native-updates redesign: additive plumbing with no behavior change. The new API is implemented on top of the existing storage (_suspendNativeUpdatesCount as the holds, _suspendedUpdates as the dirty set), so every existing code path produces the same native calls, in the same order, with the same <name>Change timing. Six commits, each green on its own; review commit by commit:

1. test(core): add native-update oracle specs — golden [setNative]/<name>Change sequences for every setter kind, load/unload/reload, batch, reset, shorthand, inheritance, keyframes. These specs are byte-identical from commit 1 to HEAD and pass at every commit.
2. refactor(core): unify native property routing — the six copies collapse into one routing function; applyPendingNativeSetters/applyAllNativeSetters share the default-capture helper.
3. feat(core): add commitNativeUpdates hook and NativeUpdateBatch — ViewBase.commitNativeUpdates(batch) is the ordering hook (override, apply what the class cares about, super applies the rest). onResumeNativeUpdates → initNativeView builds the batch and calls it. NativeUpdateBatch: entries/has/apply/skip/previous/isMount/children (an entry is a property or an aggregate Invalidation; the name avoids "target", which means a view elsewhere in core). Previous values are recorded only for nodes that can read them back (a class overriding the hook, or a property declaring invalidates), so default nodes allocate nothing extra in a batch or across unload/reload.
4. feat(core): add NativeUpdates scheduler and flushNativeUpdates — NativeUpdates.batch()/begin()/end()/flush() coalesce writes per node across nodes (implemented as _batchUpdate semantics per touched node); mode is 'sync' only. ViewBase.flushNativeUpdates({ subtree, force }); force pushes to an existing native view while the node is not loaded and leaves the holds in place.
5. feat(core): add invalidates option to properties — PropertyOptions.invalidates?: Invalidation[] on every property kind; a node handles an aggregate with [invalidation.apply](batch). No core property declares one yet.
6. perf(core): commit without a batch for nodes that cannot observe one — a node whose class uses the default hook and has no pending aggregate invalidation cannot observe a NativeUpdateBatch, so its commit runs the existing sweeps directly (same order) instead of building one.

Fast path. A live set on a class that does not override commitNativeUpdates, with no aggregate invalidations and no open batch, still calls [setNative] straight from the setter with no allocation.

Legacy surface kept (names, types, exports, semantics): _suspendNativeUpdatesCount, _suspendedUpdates, SuspendType (moved to view-base/suspend-type.ts, still internal), _batchUpdate, _suspendNativeUpdates, _resumeNativeUpdates, onResumeNativeUpdates, initNativeView, applyPendingNativeSetters, applyAllNativeSetters, affectsLayout timing.

Points for reviewers

• Cost, measured jitless (VITEST_NO_OPT=1, interpreter-only like iOS) with a no-op setNative, medians. Live setter: roughly +40–60 ns per set from collapsing six inlined copies into one routing call (JIT: within noise); a real native write is microseconds, so the relative impact in apps is far smaller. Commit path (per view, µs), base → without commit 6 → with commit 6:

  scenario	base	c5	c6
  load: construct + 8 props + _setupUI + callLoaded	7.8	10.2	9.4
  reload: unload + 4 props + load	4.3	5.7	5.0
  _batchUpdate, 8 props, live view	3.44	5.20	4.12

  The residual over base is two helper calls per property in the sweep; inlining the default-capture into those helpers would recover most of it at the cost of duplicating it, deliberately not done in Phase 0. The setter numbers live in native-updates-hot-path.spec.ts, the commit-path ones in native-updates-commit-cost.spec.ts; both print on every run.

• invalidates is additive: a property that declares it still runs its own [setNative], then the aggregates. Whether aggregates should replace the property's own setter is a Phase 1 decision.

• Dirty state is cleared before the commit runs, so a write made from a handler queues against a fresh set (previously the set was replaced after the sweep). Only observable if a setNative handler runs _batchUpdate on the same node mid-sweep.

• Property.set with an override present routes through the commit and uses pending semantics (value re-read at commit). Only affects classes that opt in.

• Device tests (apps/automated/src/ui/lifecycle/lifecycle-tests.ts: NativeUpdates.batch equals _batchUpdate counts, flush inside a batch, forced flush while unloaded) are added but were not run here. The existing lifecycle suite there asserts exact setNative counts through XML inflation, _batchUpdate, navigation and CSS class changes and is the production check for "same native calls". To run on iOS and Android before undrafting.

Tests: 485 → 557 passing (npx vitest run in packages/core), no pre-existing failures. Typecheck: npx tsc -p packages/core/tsconfig.lib.json --noEmit clean.

Related: #11412 (origin on PropertyChangeData, independent), #11413 (InheritedProperty reset cascade fix, found on the way).