[WIP] [Performance] Pre-mount new expense destinations behind confirmation RHP

[JakubKorytko]

Explanation of Change

Improves confirmation RHP destination pre-mounting for new 1:1 chats and employer workspaces. It reuses stable optimistic report IDs, safely promotes draft reports for rendering, suppresses premature report fetching, cleans interrupted promotions, and disables native RHP swipe-back while a pre-insert is active to prevent flashes or stuck loading states.

Fixed Issues

$ TBA
PROPOSAL: N/A

Tests

1. On a narrow layout, use an account that has no existing chat with another user, click the global +, select Create expense, enter an amount, and choose that user as the recipient.
2. On the confirmation page, click Create expense.
3. Verify that the new recipient chat opens with the created expense without flashing the previous page. A brief loading state is fine; getting stuck on it is not.

---

1. On a narrow layout, use an account with the SUBMIT_2026 beta enabled and no existing workspace, open a tracked expense in the self chat, and click Submit to my employer.
2. Complete the expense details and click Create expense on the confirmation page.
3. Verify that the newly created workspace expense chat opens immediately with the expense. A brief loading state is fine; getting stuck on it is not.

---

1. On iOS native, repeat either flow through the confirmation page and attempt to swipe away the entire RHP from the screen edge before submitting.
2. Use the visible back button to leave the flow, then open it again and submit the expense.
3. Verify that the native swipe does not reveal the pre-mounted destination, backing out does not leave a speculative report visible, and the later submission opens the correct destination.

Offline tests

1. On a narrow layout, start the new-recipient scenario from the Tests section and reach the confirmation page while online.
2. Disable the network connection, then click Create expense.
3. Verify that the new chat opens with the optimistic expense without flashing the previous page or remaining on a loading screen, and that the expense syncs after reconnecting.

QA Steps

Same as tests

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
  • I added steps to cover failure scenarios (i.e. verify an input displays the correct error message if the entered data is not correct)
  • I turned off my network connection and tested it while offline to ensure it matches the expected behavior (i.e. verify the default avatar icon is displayed if app is offline)
  • I tested this PR with a High Traffic account against the staging or production API to ensure there are no regressions (e.g. long loading states that impact usability).
• 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
• I verified there are no console errors (if there's a console error not related to the PR, report it or open an issue for it to be fixed)
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  • I verified that any new or modified comments were clear, correct English, and explained "why" the code was doing something instead of only explaining "what" the code was doing.
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• I followed the guidelines as stated in the Review Guidelines
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• I added unit tests for any new feature or bug fix in this PR to help automatically prevent regressions in this user flow.
• If the main branch was merged into this PR after a review, I tested again and verified the outcome was still expected according to the Test steps.

Screenshots/Videos

Android: Native

Android: mWeb Chrome

iOS: Native

iOS: mWeb Safari

MacOS: Chrome / Safari

[JakubKorytko]

@codex review

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 946460a7b6

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[codecov]

Codecov Report

❌ Looks like you've decreased code coverage for some files. Please write tests to increase, or at least maintain, the existing level of code coverage. See our documentation here for how to interpret this table.

Files with missing lines	Coverage Δ
src/ONYXKEYS.ts	100.00% <ø> (ø)
src/ROUTES.ts	22.98% <100.00%> (+0.13%)	⬆️
src/libs/ExportOnyxState/common.ts	80.35% <ø> (ø)
...on/AppNavigator/Navigators/RightModalNavigator.tsx	0.00% <ø> (ø)
...mation/getSubmitExpensePreMountDestinationRoute.ts	100.00% <100.00%> (ø)
src/setup/index.ts	100.00% <100.00%> (ø)
src/pages/inbox/ReportFetchHandler.tsx	87.00% <85.71%> (-0.05%)	⬇️
src/libs/actions/Report/index.ts	71.80% <0.00%> (+0.27%)	⬆️
src/libs/cleanupPromotedDraftReports.ts	70.00% <70.00%> (ø)
.../request/step/confirmation/useExpenseSubmission.ts	72.31% <36.36%> (-0.94%)	⬇️
... and 1 more
... and 7 files with indirect coverage changes

[JakubKorytko]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Breezy!

Reviewed commit: d77efce009

ℹ️ About Codex in GitHub

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