[POC] react navigation 8 pauseWhenCovered

[LukasMod]

Explanation of Change

Explanation of Change

Why: screens under the RHP re-render on every Onyx write during interactions — ManualSendMessage 626 ms on web, 1289 ms on iOS, 940 ms on Android. Stock v8 can't pause them on either platform: both stack implementations keep covered/before-last screens live, and neither can see a cover coming from an ancestor navigator.

What: patched pauseWhenCovered screen option, on web and native — pauses a screen via React <Activity mode="hidden"> (subscriptions unmounted, renders deferred to idle) while keeping it painted. Applied per-screen to the same 5 heavy list screens on all platforms (report chat, Search listing, 3 report RHP screens). Onyx updates aren't lost, just deferred — paused screens still re-render at idle priority and pull fresh data, so content under the blur stays up to date off the critical path.

How: three patches —

• stack (web CardStack): pause flagged screens when covered in-stack or by an ancestor's cover via IsFocusedContext; + dontDetachScreen so split sidebars survive.
• native-stack (NativeStackView): same two branches, plus native-only cover exclusions — sheets, iPad/form-sheet modals, dismissing screens. Keep-visible and the 500 ms delay come from stock ActivityView.native, which neutralizes display: none via a display: contents view config instead of web's MutationObserver.
• core: per-layer {web, native} options conversion — without it v8 silently drops every platform-nested option, and it's the path the new native: flags travel.

Native also forced react-native-gesture-handler 3.1.0 — a hard peer requirement of v8's stack (>= 3.0.0) — whose Legacy* re-export rename touched 11 call sites and needed a 4th react-native-draggable-flatlist patch.

Result: send-message, same scenario on a heavy account:

Platform	Baseline	RN8	Improvement
Web	626 ms	159 ms	−74.6%
iOS	1289 ms	735 ms	−42.9%
Android	940 ms	453 ms	−51.7%

Cost: pause re-runs effects on resume — mount-effect/cleanup idioms need ref guards (3 fixed on web); Reanimated exit animations flicker under pause on web (stopgap: disabled on Expense listing). Pause logic is now duplicated across two stack implementations.

PoC scope: 3 of the 15 v7 react-navigation patches re-evaluated/ported, no TypeScript fixes after the navigation bump (typecheck deliberately skipped), and no native regression sweep yet — the effect-lifetime failure classes and the RNGH 3 gesture call sites were only verified on web.

Fixed Issues

$ #97081
PROPOSAL:

Tests

• Verify that no errors appear in the JS console

Offline tests

QA Steps

// TODO: These must be filled out, or the issue title must include "[No QA]."

• Verify that no errors appear in the JS console

PR Author Checklist

• I linked the correct issue in the ### Fixed Issues section above
• I wrote clear testing steps that cover the changes made in this PR
  • I added steps for local testing in the Tests section
  • I added steps for the expected offline behavior in the Offline steps section
  • I added steps for Staging and/or Production testing in the QA steps section
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• I included screenshots or videos for tests on all platforms
• I ran the tests on all platforms & verified they passed on:
  • Android: Native
  • Android: mWeb Chrome
  • iOS: Native
  • iOS: mWeb Safari
  • MacOS: Chrome / Safari
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Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

[github-actions]

⚠️ This PR is possibly changing native code and/or updating libraries, it may cause problems with HybridApp. Please check if any patch updates are required in the HybridApp repo and run an AdHoc build to verify that HybridApp will not break. Ask Contributor Plus for help if you are not sure how to handle this. ⚠️