feat(mobile): forward reviewer search to the server in the inbox reviewer picker (port #2800)

[Gilbert09]

Summary

Ports desktop #2800 ("fix(inbox): forward reviewer search query to the server") to the React Native / Expo mobile app.

The inbox "Add reviewer" picker previously fetched the available-reviewers list once and filtered it client-side only, so typing a name that wasn't on the already-fetched page returned no results. This forwards the search query to the server (the available_reviewers endpoint already accepts a query param), making the server the source of truth — matching #2800's intent.

Changes

• useAvailableSuggestedReviewers now accepts a query option, includes it in the React Query queryKey (so distinct searches cache separately), and forwards it to getAvailableSuggestedReviewers(query).
• EditReviewersSheet debounces the search input (250ms via a small useDebouncedValue hook) and passes it into the hook; the client-side filter is removed. Loading uses isFetching so the spinner shows while a server search is in flight.
• Scoped the 60s background poll to the unfiltered list only, so transient search terms don't each spawn their own background poller.
• ReviewerFilterSheet (no search box) is unchanged — it calls the hook with no query and keeps fetching the full list.

Scope

Mobile only — no desktop or shared-package changes.

Testing

• New useInboxReports.test.ts verifies the hook forwards a trimmed query and omits the param when empty.
• pnpm --filter @posthog/mobile test src/features/inbox → 52 passed.
• Biome lint clean; typecheck clean for the changed files.

[github-actions]

React Doctor found 1 issue in 1 file · 1 warning.

1 warning

src/features/inbox/components/EditReviewersSheet.tsx

• ⚠️ src/features/inbox/components/EditReviewersSheet.tsx:105 Non-virtualized mapped list in ScrollView rn-no-scrollview-mapped-list

_{Reviewed by React Doctor for commit 7e08c3a.}

[greptile-apps]

Prompt To Fix All With AI

Fix the following 3 code review issues. Work through them one at a time, proposing concise fixes.

---

### Issue 1 of 3
apps/mobile/src/features/inbox/components/EditReviewersSheet.tsx:86-95
**Spinner flickers on background poll when the reviewer list is empty**

`isFetching` is `true` for every in-flight fetch — including the 60-second background polls. If the available-reviewer list genuinely comes back empty (e.g. a small team, an org-level filter, or a permissions edge case), the "No users found" message disappears and is replaced by a spinner for the duration of every background poll.

The original code used `isLoading`, which React Query only sets `true` when there is no cached data yet (i.e. the very first fetch). Replacing it with `isFetching` removes that guard. The fix is to check `available === undefined` alongside `isFetching`, or to destructure `isLoading` from the hook return (which in v5 is `status === 'pending'`).

### Issue 2 of 3
apps/mobile/src/features/inbox/components/EditReviewersSheet.tsx:86-96
Use `available === undefined` (no data yet) to gate the spinner so it only shows on the true first-load state, not on every subsequent background poll that returns an empty list.

```suggestion
        {options.length === 0 ? (
          available === undefined && isFetching ? (
            <View className="flex-1 items-center justify-center">
              <ActivityIndicator size="large" color={themeColors.accent[9]} />
            </View>
          ) : (
            <View className="flex-1 items-center justify-center p-6">
              <Text className="text-[14px] text-gray-10">No users found</Text>
            </View>
          )
        ) : (
```

### Issue 3 of 3
apps/mobile/src/features/inbox/hooks/useInboxReports.test.ts:36-51
**Tests should be parameterised**

Both test cases exercise the same flow (input query → expected call argument) and differ only in their data. This is a good candidate for `it.each`, which keeps the logic in one place and makes adding new cases trivial.

_{Reviews (1): Last reviewed commit: "feat(mobile): forward reviewer search to..." | Re-trigger Greptile}