test(desktop): keyboard community reorder flakes before retry

## Summary

`desktop/tests/e2e/community-rail.spec.ts` intermittently fails the keyboard-reorder assertion on its first Playwright attempt, then passes on retry.

## Reproduction

Test:

```text
community rail › keyboard reorder: Space to pick up, ArrowUp to move, Space to drop updates stored order
```

Control commit: parked `max/tui-renderer` head `90896bebecc6c56a62cf3b27992d074eccc1477c`.

Command (after a clean E2E build, with a fresh CI-mode web server):

```bash
cd desktop
CI=1 pnpm exec playwright test tests/e2e/community-rail.spec.ts \
--project=smoke \
--grep 'keyboard reorder' \
--repeat-each=20 \
--reporter=list
```

Observed: **8/20 first attempts failed**, and all eight passed on Playwright retry.

## Failure signature

The expected persisted order is:

```text
["ws-b", "ws-a"]
```

The failed attempts time out after 5 seconds with the original order still present:

```text
["ws-a", "ws-b"]
```

Assertion location: `desktop/tests/e2e/community-rail.spec.ts`, final localStorage poll in the keyboard-reorder test.

## Attribution

This reproduced on `90896bebe`, before the composed channel-validation latch test change in PR #4525. The control worktree was clean before the run and `git diff --quiet HEAD` passed afterward, so this is independent of that latch composition.