chore: remove misleading Node 10 TODO comments

[ConnorQi01]

Summary

• Replace TODO comment in appWorker.ts (WORKER_BOOTSTRAP string) with an explanation
  that the polyfill is required because the code runs in the user's RN environment where
  import/require are unavailable.
• Replace TODO comment in forkedAppWorker.ts with an explanation that the simple
  file:// string concatenation is intentionally kept to avoid URL encoding side-effects
  from url.pathToFileURL().

Files changed

• src/debugger/appWorker.ts
• src/debugger/forkedAppWorker.ts

Test plan

• Run gulp build — no errors
• Verify no functional behavior changed (comments only)

[ConnorQi01]

/azp run

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