Update sync settings screen with new recovery section

[CDRussell]

Task/Issue URL: https://app.asana.com/1/137249556945/project/72649045549333/task/1211766481496465

Description

Adds a new Recovery section to the signed-in Sync & Backup settings screen. The section contains:

• Restore on App Reinstall toggle — when enabled, persists the recovery payload to Block Store. When disabled, clears any existing payload. Gated by syncAutoRestore FF and Block Store availability.
• Download Recovery Code as PDF item (previously in the root of the settings screen)
• Data expiration caption

When the settings screen is exited, if the toggle state has changed, the recovery payload is saved to or cleared from Block Store accordingly.

The toggle defaults to ON when set up via the new recovery screen during sync setup, and OFF for existing signed-in users seeing it for the first time (i.e. the FF was disabled during their initial setup).

Steps to test this PR

Notes

• Prerequisites: Internal build installed on a device with Google Play Services, logged into a Google account.
• Navigate to Settings > Sync Dev Settings to access Block Store controls.
• ℹ️ Clearing app data does not restore Block Store data; it must be an uninstall/reinstall.
• Suggested logcat filter: Sync-Recovery|Sync-AutoRestore

Scenario 1: syncAutoRestore OFF — Recovery section shown, no toggle

• Fresh install internal variant; syncAutoRestore FF is disabled by default
• Sign in to Sync & Backup
• Navigate to Settings > Sync & Backup
• Verify a Recovery section is visible containing the PDF download item and expiration caption
• Verify the Restore on App Reinstall toggle is not visible

Scenario 2: syncAutoRestore ON, existing user — toggle visible, defaults OFF

• Sign in to Sync & Backup with syncAutoRestore FF disabled, then enable it via FF inventory
• Navigate to Settings > Sync & Backup
• Verify the Restore on App Reinstall toggle is visible and OFF by default
• Enable the toggle and navigate away (press Back)
• Go to Sync Dev Settings → verify Block Store shows a JSON payload containing both recovery_code and device_id

Scenario 3: Toggle turned OFF — payload cleared

• With syncAutoRestore ON and payload already saved (from Scenario 2)
• Navigate to Settings > Sync & Backup
• Verify the toggle is ON (state persisted)
• Disable the toggle and navigate away
• Go to Sync Dev Settings → verify Block Store is empty

Scenario 4: No change — no storage operations

• Navigate to Settings > Sync & Backup, leave the toggle unchanged, and exit
• Go to Sync Dev Settings → verify Block Store contents are unchanged

UI changes

Auto restore, available+enabled	Auto restore, available+disabled	Auto restore, disabled

[CDRussell]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Update sync settings screen with new recovery section #8008 👈 (View in Graphite)
• Add new sync screen for showing recovery code #7966
• Prevent orphaned sync devices when auto-restoring #7969
• Headless sync recovery implementation #7941
• Sync auto recovery detection in onboarding #7925
• Add SyncAutoRestore API and SyncRecovery key #7910
• develop

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