fix: refetch contacts after hiding inbox, redirect to most recent chat

After hiding a contact inbox, the contacts list now refetches immediately
so the hidden contact disappears reactively. When the current contact is
removed from the list, the selection jumps to the most recently active
contact (by lastContactAt) instead of the first item in the current sort.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/app/composables/useContactInboxes.ts

@@ -19,7 +19,7 @@ export type ContactInbox = {
   updatedAt: string;
 };
 
-export function useContactInboxes(opts: { apolloAuthReady: ComputedRef<boolean> }) {
+export function useContactInboxes(opts: { apolloAuthReady: ComputedRef<boolean>; onHidden?: () => void }) {
   const { result: contactInboxesResult, refetch: refetchContactInboxes } = useQuery(
     ContactInboxesQueryDocument,
     null,
@@ -60,6 +60,7 @@ export function useContactInboxes(opts: { apolloAuthReady: ComputedRef<boolean>
     inboxToggleLoadingById.value = { ...inboxToggleLoadingById.value, [id]: true };
     try {
       await doSetContactInboxHidden({ inboxId: id, hidden });
+      if (hidden && opts.onHidden) opts.onHidden();
     } catch (e: unknown) {
       console.error("[setInboxHidden] mutation failed:", e);
     } finally {