fix(build): preserve watch paths and finish asset copies before returning

[OskarEichler]

Fixes

Pass watch rebuild paths as argv through the current Node executable; resolve deleted outputs relative to the package source directory; copy non-JS assets synchronously and retain launcher executable permissions.

Compatibility and observable changes

Developer tooling only. Existing Windows glob PR #2827 is not duplicated.

Verification

• Applied this patch independently to main at 9013a480c66aece0e23cc8082ee23f92274e3cf4; 2 focused actual-source controls passed. The published tree matches the independently verified local tree exactly, including executable permissions.
• Combined source build and existing unit suite passed: 56 suites, 314 tests, one todo, 62 snapshots. Full ESLint passed with two pre-existing warnings (an unchanged test URL and an unchanged template-version quote). No tests/specs/snapshots were added, changed or suppressed.
• Standalone diagnostics reproduced the relevant failures or unnecessary work on the unmodified baseline and were kept outside the repository.
• Broad end-to-end invocation was stopped while an external dependency install stalled; it is not reported as passing. Real device/profile interaction, physical-device behavior, Windows execution and hosted CI remain unverified.
• Consumer verification on RN 0.87.1: integrity-verified 20.2.0 package artifacts with the reviewed overlays are now installed using immutable commit pins; all 392 installed files match. Before/after native autolinking configurations are identical (27 Android / 26 iOS dependencies). Immutable install, ESLint, CocoaPods, all 13 production web targets, four browser extensions, both Android Debug flavors, both unsigned iOS arm64 Simulator Debug schemes and all four production Metro bundles pass. Existing peer/export-map/build warnings remain; Xcode recovered from a cached bridging-header diagnostic and exited successfully. No signing, physical-device certification, app push or deployment. Strict XML validation draft fix(android): reject invalid manifest XML before parsing #2844 is excluded from these artifacts.
• Consumer artifact commits (OskarEichler/cli): CLI de1aabb75931032240c3b9daefc0cf77276935cd; platform Android 0d92368fb31e92edbea9bfb002392c891688bd82; config 5ef410e4f719a4ab87591b01ebfbacf1d18fa8be; config Android 946a49e5ad888b535274ff1d7977e680683a0d38; tools c05d7c087c4c14a736b8a6f82ce10f0e340a05b6. These are package artifacts, not additional source changes in this PR.

Type: fix

No React Native, native SDK, or package version bump is included.