Add sync with another device UI

[MiSikora]

Task/Issue URL: https://app.asana.com/1/137249556945/project/1216103556496795/task/1216955031318054?focus=true
Tech Design URL (if applicable): https://app.asana.com/1/137249556945/project/1216103556496795/task/1216509582049467?focus=true
API Proposals URL(s) (if applicable): N/A

Description

Adds the real UI for the connecting screen in the simplified Sync With Another Device flow. The screen opens after a valid sync code is recognized, either scanned on the "Scan QR" tab or pasted on the "Enter Code" tab. The screen shows a lock animation that plays once, a headline reading "Sync & Backup is end-to-end encrypted on all your devices.", and a "Connecting…" label with a spinner next to it. The actual connection logic is not part of this PR, so the screen stays in the connecting state.

Steps to test this PR

Sync in progress UI

• Open Sync Dev Settings.
• Tap "Launch Sync Settings V2".
• Tap "Sync With Another Device".
• Complete the device authentication prompt.
• On the "Scan QR" tab, tap "I’m Ready to Scan".
• Scan a sync QR code shown by another device.
• Verify the connecting screen opens with a lock animation that plays once.
• Verify the headline reads "Sync & Backup is end-to-end encrypted on all your devices.".
• Verify a spinner is shown next to the "Connecting…" label below the headline.

UI changes

---

Note

Low Risk
Presentation-only changes in sync v2 UI with no new networking, crypto, or state transitions; connection behavior is intentionally deferred.

Overview
Replaces the placeholder ExchangeSyncCodeActivity UI (magenta background and raw sync URL text) with the real connecting screen for the simplified Sync With Another Device flow.

The activity now uses activity_sync_v2_exchange_sync_code.xml: a one-shot Lottie lock animation, an E2E encryption headline, and a Connecting… line with a Material circular progress indicator on the label. Edge-to-edge for the Sync bucket is wired through EdgeToEdgeProvider / EdgeToEdgeHandler like other sync v2 screens.

New copy lives in donottranslate.xml (sync_another_device_v2_headline / sync_another_device_v2_body). No sync exchange or connection logic is added here—the screen stays in the connecting state after a valid code is scanned or pasted.

^{Reviewed by Cursor Bugbot for commit e4f7064. Bugbot is set up for automated code reviews on this repo. Configure here.}

[MiSikora]

• Replace ScrollView with NestedScrollView in sync settings #9424
• Simplified sync translations #9414
• Parameterize sync pixels tests #9413
• Apply correct edge to edge handling in simplified sync #9412
• Add simplified sync pixels #9401
• Clean up sync code before integrating pixels #9386
• Avoid signing out of a device when renaming it #9374
• Handle simplified sync deep linking #9373
• Handle restore on reinstall sync scenario #9368
• Simplified sync UI updates #9363
• Handle v1 exchange sync codes #9362
• Handle sync recovery basic scenario #9356
• Add syncing with another device logic and navigation #9343
• Add generic handling of v1 sync errors #9337
• Add sync with another device UI #9334 👈 (View in Graphite)
• Detect scanned QR sync codes #9333
• Handle sync code pasting #9332
• Refactor simplified sync class names #9329
• Handle sync logic on the displayed QR code page #9328
• Display sync QR code in simplified sync #9321
• Make remove device dialog destructive #9317
• Mitigate sync settings UI race condtions #9316
• develop

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Cursor Bugbot has reviewed your changes and found 1 potential issue.

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[MiSikora]

Merge activity

• Aug 4, 12:40 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Aug 4, 12:43 PM UTC: Graphite rebased this pull request as part of a merge.
• Aug 4, 12:54 PM UTC: @MiSikora merged this pull request with Graphite.