fix(desktop): order unnamed roster members by full canonical npub (#7503)

🤖

## Summary

- Channel members appear in the Members sidebar. A member who has never
set a display name is listed under an abbreviated form of their public
key (npub), and the sidebar previously sorted those unnamed members by
that short label. Short labels are not unique — different keys can share
one — so the order of unnamed members could look arbitrary or unstable.
Unnamed members now sort by their full public key, so the order is
deterministic.
- When two members display the same name, the previous tiebreak was
membership order (who joined first), which is not visible to a reader
and can shift as roster data loads in. The tiebreak is now the full
public key, so identical display names always land in the same order.
- Nothing gets noisier on screen: the full key is used only for sorting,
and the sidebar still shows the compact abbreviated form. Priorities are
unchanged — authored (custom) names still outrank fallback labels, and
role/current-user grouping still applies.
- Scope is the desktop app's Members sidebar and member management: the
two existing sort comparators. Mobile and other lists in the app are
untouched.

### Related issue

Based on #7495 (introduced the abbreviated npub labels this follows up
on). The original five presentation PRs remain independently reviewable.
No closer duplicate found.

### Testing

- 6469 desktop unit tests, typecheck, and check pass.
- The 3 existing consumer-seam E2E tests still pass; a new E2E test
asserts the sidebar lists unnamed members in full-key order, with
fixture members deliberately inserted in the opposite order so incoming
membership order cannot mask the sort.
- Negative check: reverting only this change makes the new ordering
assertion fail, so it genuinely binds the new sort.
- CI has not run on this PR yet.

Buzz provenance: channel 1f0e4a3d-7e01-4efe-bb16-843b357f85c9 / task
340c3de9b27dbedb8453c0c7652220f9080d30fcc70a7c4f6e27fdd4fa378056

---------

Signed-off-by: Logan Johnson <loganj@squareup.com>
Co-authored-by: Larry <627498bd4bd1f281a16431e3c6cce3b5c25b6692798c78672298aefbf2f8f8b5@buzz.block.builderlab.xyz>

.github/workflows/_ci-desktop.yml

@@ -24,7 +24,10 @@ jobs:
   desktop-core:
     name: Desktop Core
     runs-on: ubuntu-latest
-    timeout-minutes: 45
+    # The compiled-flag verification step rebuilds the workspace for each
+    # BUZZ_BUILD_* state and runs the full suite under all three compile
+    # states; the complete recipe needs ~46m, so budget 60m.
+    timeout-minutes: 60
     if: github.event_name == 'push' || inputs.desktop || inputs.desktop_rust || inputs.rust
     permissions:
       contents: read