sync(common-v8): cautious wave2 runtime sync (no-eslint)

[miccy]

Summary

Wave2 is a cautious runtime-focused sync from upstream/common-v8 on top of Wave1.

Scope is intentionally small and excludes ESLint v10.

PORTED

• 904c47e Add arrayFromAsync and tests
• 012108c React Native: isolate worker runs and add tests (selective, fork-compatible)
• 58b0fe3 Remove stray console.log of Symbol.asyncDispose (no-op in this fork, tracked explicitly)

DEFERRED

• 87f87d5 Add array/promise polyfills and remove runtime checks (Wave2b)
• 0d6d853 Create .gitignore (non-blocking, defer with example cleanup)

SKIPPED

• 3c0f25c ESLint v10 upgrade (explicitly out of scope)

Risks and Mitigations

• RN worker/local-auth flow impact from 012108c
  • Mitigation: targeted RN shared test + full test run + expo web export
• Additive API export mismatch for arrayFromAsync
  • Mitigation: build + targeted array tests + full test run
• Lockfile drift
  • Mitigation: no extra dependency bumps added in this wave

Test Results

• bun run build ✅
• bun run test ✅
• bun run lint ✅ (4 existing warnings in packages/react-native/test/Polyfills.test.ts, no errors)
• bun run coverage:lane:active ✅
• (cd examples/react-expo && bun run web:export) ✅
• bunx vitest run --project react-native packages/react-native/test/shared.test.ts ✅
• bunx vitest run packages/common/test/Array.test.ts ✅

Notes

• PR is stacked on top of Wave1 (#58) and targets sync/common-v8-2026-03-01-wave1 as base.
• After Wave1 merge, this PR can be retargeted to main.

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✨ Finishing Touches

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