Files
b42b093613 feat(mobile): sync per-group channel sorting (#4231)
**Category:** improvement
**User Impact:** Mobile users can sort each channel group by recent
activity or A–Z, with their choices synchronized with desktop.
**Problem:** Desktop supports persistent per-group channel sorting, but
mobile shows the same groups without equivalent controls or shared
preferences. The earlier mobile attempt coupled sorting to unsafe
dirty-state behavior that could overwrite newer cross-client changes.
**Solution:** Add mobile sorting controls and encrypted NIP-78
synchronization using the existing desktop `channel-sort` contract,
while retaining ordinary whole-blob last-write-wins behavior. Local
state is scoped by identity and normalized relay, startup closes
fetch/subscription gaps, and both clients use the same deterministic
ordering rules.

<details>
<summary>File changes</summary>

**desktop/src/features/sidebar/lib/channelSortPreference.test.mjs**
Updates ordering coverage for the deterministic, cross-client A–Z
comparison rule.

**desktop/src/features/sidebar/lib/channelSortPreference.ts**
Aligns desktop channel-name collation with mobile so synchronized
preferences produce the same visible order.

**mobile/lib/features/channels/channel_sort/channel_sort_manager.dart**
Adds encrypted relay synchronization with safe startup gap handling,
clock checks, and ordinary last-write-wins conflicts.

**mobile/lib/features/channels/channel_sort/channel_sort_provider.dart**
Scopes sort state to the active identity and community lifecycle.

**mobile/lib/features/channels/channel_sort/channel_sort_storage.dart**
Defines the desktop-compatible payload, relay-scoped cache and
migration, cleanup, and shared ordering behavior.

**mobile/lib/features/channels/channels_page.dart**
Connects sort state to the channel page.

**mobile/lib/features/channels/channels_page/body.dart**
Applies each selected order to Starred, custom groups, Channels, and
DMs.

**mobile/lib/features/channels/channels_page/sections.dart**
Adds checked Recent and A–Z actions using the existing anchored-popover
UI.


**mobile/test/features/channels/channel_sort/channel_sort_manager_test.dart**
Covers payload adoption, encrypted publication, conflicts, timestamps,
retries, and cleanup.


**mobile/test/features/channels/channel_sort/channel_sort_storage_test.dart**
Covers parsing, relay isolation, migration, cleanup, and ordering modes.

**mobile/test/features/channels/channels_page_test.dart**
Verifies the group controls expose both choices.

</details>

### Reproduction steps

1. Open the mobile channel list with populated built-in and custom
groups.
2. Open a group menu and choose **Sort: Recent**; confirm active
channels move to the top.
3. Choose **Sort: A–Z**; confirm deterministic alphabetical ordering
returns.
4. Repeat for Starred, a custom group, Channels, and DMs.
5. Open desktop with the same identity and community and confirm each
synchronized preference.
6. Switch communities and confirm cached preferences do not bleed across
relays.

### Screenshots

Approved `live` custom-section flow with `research` kept offscreen.

| Recent selected | A–Z result | A–Z selected |
|---|---|---|
| ![live custom section with Recent
selected](https://d24qwcpro867f5.cloudfront.net/repos/buzz/prs/4231/live-recent-selected.png)
| ![live custom section sorted
A–Z](https://d24qwcpro867f5.cloudfront.net/repos/buzz/prs/4231/live-az-result.png)
| ![live custom section with A–Z
selected](https://d24qwcpro867f5.cloudfront.net/repos/buzz/prs/4231/live-az-selected.png)
|

### Validation

- Mobile `flutter analyze` — clean
- Focused mobile sort and channel-page suites — 37/37 passed
- Desktop full suite — 3906/3906 passed
- Mobile full suite — 1034 passed, 1 skipped, 1 unrelated baseline
failure reproduced at `ac4fa13b8`

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---------

Signed-off-by: Taylor Ho <taylorkmho@gmail.com>
Co-authored-by: npub1223z34hd7vtwc6qj4s7flsxkj644nlre2nthu7lrrmkumhu3xddsrx9r6w <52a228d6edf316ec6812ac3c9fc0d696ab59fc7954d77e7be31eedcddf91335b@buzz.block.builderlab.xyz>
2026-08-03 18:02:09 -07:00
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