Add Testing & Verification section to reviewer checklist

Group all testing-related checklist items under a dedicated section including test steps verification, platform testing, offline testing, screenshot requirements, and unit test coverage.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: adhorodyski

contributingGuides/REVIEWER_CHECKLIST.md

@@ -6,21 +6,23 @@
 - [ ] I verified that this PR follows the guidelines as stated in the [Review Guidelines](https://github.com/Expensify/App/blob/main/contributingGuides/PR_REVIEW_GUIDELINES.md)
 - [ ] 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.
 - [ ] I have checked off every checkbox in the PR reviewer checklist, including those that don't apply to this PR.
+
+### Testing & Verification
 - [ ] I verified testing steps are clear and they cover the changes made in this PR
     - [ ] I verified the steps for local testing are in the `Tests` section
     - [ ] I verified the steps for Staging and/or Production testing are in the `QA steps` section
     - [ ] I verified the steps cover any possible 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 checked that screenshots or videos are included for tests on [all platforms](https://github.com/Expensify/App/blob/main/contributingGuides/CONTRIBUTING.md#make-sure-you-can-test-on-all-platforms)
 - [ ] I included screenshots or videos for tests on [all platforms](https://github.com/Expensify/App/blob/main/contributingGuides/CONTRIBUTING.md#make-sure-you-can-test-on-all-platforms)
-- [ ] I verified that the composer does not automatically focus or open the keyboard on mobile unless explicitly intended. This includes checking that returning the app from the background does not unexpectedly open the keyboard.
 - [ ] I verified tests pass on **all platforms** & I tested again on:
     - [ ] Android: HybridApp
     - [ ] Android: mWeb Chrome
     - [ ] iOS: HybridApp
     - [ ] iOS: mWeb Safari
     - [ ] MacOS: Chrome / Safari
     - [ ] MacOS: Desktop
+- [ ] For any bug fix or new feature in this PR, I verified that sufficient [unit tests](https://github.com/Expensify/App/blob/main/tests/README.md) are included to prevent regressions in this flow.
 - [ ] If there are any errors in the console that are unrelated to this PR, I either fixed them (preferred) or linked to where I reported them in Slack
 - [ ] I verified there are no new alerts related to the `canBeMissing` param for `useOnyx`
 - [ ] I verified proper code patterns were followed (see [Reviewing the code](https://github.com/Expensify/App/blob/main/contributingGuides/PR_REVIEW_GUIDELINES.md#reviewing-the-code))
@@ -59,7 +61,7 @@
     - [ ] I verified that all the inputs inside a form are aligned with each other.
     - [ ] I added `Design` label and/or tagged `@Expensify/design` so the design team can review the changes.
 - [ ] If a new page is added, I verified it's using the `ScrollView` component to make it scrollable when more elements are added to the page.
-- [ ] For any bug fix or new feature in this PR, I verified that sufficient [unit tests](https://github.com/Expensify/App/blob/main/tests/README.md) are included to prevent regressions in this flow.
+- [ ] I verified that the composer does not automatically focus or open the keyboard on mobile unless explicitly intended. This includes checking that returning the app from the background does not unexpectedly open the keyboard.
 
 ### Screenshots/Videos
 <details>