feat(unified-mailbox): enable search in the unified views

Enable text AND advanced search in all Unified Mailbox views (the per-role
mailboxes and the folder-selected All mail / Unread / Starred cross views). The
search input was hard-disabled for every unified view; the store fan-out already
supported text search.

- page.tsx: the search text input and the advanced-filter toggle are enabled for
  all unified views (only the scheduled view stays disabled). Clear-search also
  restores a cross view (not just per-role).
- Advanced filters now apply in cross views too: new advancedSearchCrossViewEmails
  ANDs the advanced filter (text + field conditions from buildJMAPFilter, built
  without an inMailbox clause) onto the cross-view membership. Per-role unified
  views keep using advancedSearchUnifiedEmails. Both honor the filter on the first
  page, on load-more, and on the folder-switch re-run. Fixes: an active Starred
  filter not applying after switching into a cross view, and the Unread filter in
  the Unread view returning nothing.
- Search persistence on folder switch: an active search is kept and re-run in the
  target view, preserving advanced filters. handleMailboxSelect picks
  advancedSearch when filters are set (normal, per-role unified, and cross views,
  after setting the unified state), text searchEmails when only a query is set,
  and browses otherwise. The scheduled view is the only view that resets the
  search on enter (unavailable there; setScheduledView clears searchQuery +
  searchFilters).

Account scope is intentionally left unrestricted in search (it already fanned out
across all accounts); the per-view folder selection still applies via
crossIncludedMailboxIds.

FEATURES.md

@@ -6,6 +6,7 @@
 - Gmail-style threading with inline expansion and an optional conversation toggle
 - Unified Mailbox – combined Inbox, Sent, Drafts, Junk, Archive, and Trash, scoped by default to the active account and its shared/group folders, with an optional admin-gated cross-account mode that spans every connected account
 - Aggregated All mail / Unread / Starred entries in the Unified Mailbox – scoped by the same account boundary (or all accounts in cross-account mode) and narrowed by a per-account folder selection; each list labels the source folder of every message
+- Search inside the Unified Mailbox – text search across every unified view (the per-role mailboxes and the folder-selected All mail / Unread / Starred lists); advanced filters are additionally available in the per-role unified mailboxes
 - Three selectable mail layouts: split (three-pane), focused list, and reading pane at bottom
 - Draft auto-save with identity preservation, persisted HTML body, and proper `In-Reply-To` / `References` headers on replies
 - Attachment upload, download, drag-out to local file system, and inline preview – images, inline PDF on desktop and mobile, composer attachments (click to open), and `.eml` (`message/rfc822`) attachments rendered like an email; image thumbnails and forgotten-attachment warning

app/(main)/[locale]/page.tsx

@@ -1838,7 +1838,18 @@ export default function Home() {
       }
 
       const populated = await buildPopulatedUnifiedAccounts();
-      await fetchUnifiedEmailsAction(populated, role);
+      // Keep an active search across the switch and re-run it in this view
+      // (mirrors normal mailboxes), preserving advanced filters; otherwise browse.
+      if (client && (!isFilterEmpty(searchFilters) || searchQuery)) {
+        useEmailStore.setState({ isUnifiedView: true, unifiedRole: role, crossView: null });
+        if (!isFilterEmpty(searchFilters)) {
+          await advancedSearch(client);
+        } else {
+          await searchEmails(client, searchQuery);
+        }
+      } else {
+        await fetchUnifiedEmailsAction(populated, role);
+      }
       refreshUnifiedCounts(populated);
       return;
     }
@@ -1860,7 +1871,18 @@ export default function Home() {
       }
 
       const populated = await buildPopulatedUnifiedAccounts();
-      await fetchCrossViewAction(populated, view);
+      // Keep an active search across the switch and re-run it in this view
+      // (mirrors normal mailboxes), preserving advanced filters; otherwise browse.
+      if (client && (!isFilterEmpty(searchFilters) || searchQuery)) {
+        useEmailStore.setState({ isUnifiedView: true, crossView: view, unifiedRole: null });
+        if (!isFilterEmpty(searchFilters)) {
+          await advancedSearch(client);
+        } else {
+          await searchEmails(client, searchQuery);
+        }
+      } else {
+        await fetchCrossViewAction(populated, view);
+      }
       refreshCrossCounts(populated);
       return;
     }
@@ -2206,13 +2228,16 @@ export default function Home() {
     setSearchQuery("");
     clearSearchFilters();
     if (!client) return;
-    // In unified view the active "mailbox" is a virtual role, so refresh via
+    // In unified view the active "mailbox" is a virtual role or cross view, so
-    // the unified fan-out instead of fetchEmails.
+    // refresh via the unified fan-out instead of fetchEmails.
     if (isUnifiedView) {
+      const populated = await buildPopulatedUnifiedAccounts();
       const role = useEmailStore.getState().unifiedRole;
+      const cross = useEmailStore.getState().crossView;
       if (role) {
-        const populated = await buildPopulatedUnifiedAccounts();
         await fetchUnifiedEmailsAction(populated, role);
+      } else if (cross) {
+        await fetchCrossViewAction(populated, cross);
       }
       return;
     }
@@ -2848,8 +2873,8 @@ export default function Home() {
                       className={cn("ps-9 h-9", searchQuery && "pe-8")}
                       data-search-input
                       data-tour="search-input"
-                      disabled={isUnifiedView || isScheduledView}
+                      disabled={isScheduledView}
-                      title={isUnifiedView ? t("unified_mailbox.search_unavailable") : isScheduledView ? t('email_viewer.scheduled_actions_only') : undefined}
+                      title={isScheduledView ? t('email_viewer.scheduled_actions_only') : undefined}
                     />
                     {searchQuery && (
                       <button
@@ -2865,15 +2890,15 @@ export default function Home() {
                   <button
                     type="button"
                     onClick={toggleAdvancedSearch}
-                    disabled={isUnifiedView || isScheduledView}
+                    disabled={isScheduledView}
                     className={cn(
                       "relative flex-shrink-0 p-2 rounded-md transition-colors",
-                      (isUnifiedView || isScheduledView) && "opacity-50 cursor-not-allowed",
+                      isScheduledView && "opacity-50 cursor-not-allowed",
                       isAdvancedSearchOpen || activeFilterCount(searchFilters) > 0
                         ? "bg-primary/10 text-primary"
                         : "text-muted-foreground hover:text-foreground hover:bg-muted"
                     )}
-                    title={isUnifiedView ? t("unified_mailbox.search_unavailable") : isScheduledView ? t('email_viewer.scheduled_actions_only') : t("advanced_search.toggle_filters")}
+                    title={isScheduledView ? t('email_viewer.scheduled_actions_only') : t("advanced_search.toggle_filters")}
                   >
                     <Filter className="w-4 h-4" />
                     {!isAdvancedSearchOpen && activeFilterCount(searchFilters) > 0 && (

lib/__tests__/unified-mailbox-cross.test.ts

@@ -6,6 +6,7 @@ import {
   buildCrossFilter,
   getCrossUnreadTotal,
   fetchCrossViewEmails,
+  advancedSearchCrossViewEmails,
   resolveSourceFolderName,
   type UnifiedAccountClient,
 } from '@/lib/unified-mailbox';
@@ -203,3 +204,28 @@ describe('fetchCrossViewEmails', () => {
     expect(result.errors.get('bad')).toBe('boom');
   });
 });
+
+describe('advancedSearchCrossViewEmails', () => {
+  it('ANDs the advanced filter onto the cross-view membership', async () => {
+    const advancedSearchEmails = vi.fn().mockResolvedValue({ emails: [], total: 0, hasMore: false });
+    const a = makeAccount({ accountId: 'a', mailboxes: [mb('inbox', 'inbox')] }, { advancedSearchEmails });
+
+    await advancedSearchCrossViewEmails([a], 'all', { hasKeyword: '$flagged' }, 50, 0);
+
+    const [filter] = advancedSearchEmails.mock.calls[0];
+    expect(filter).toEqual({
+      operator: 'AND',
+      conditions: [{ inMailbox: 'inbox' }, { hasKeyword: '$flagged' }],
+    });
+  });
+
+  it('uses only the membership filter when the extra filter is empty', async () => {
+    const advancedSearchEmails = vi.fn().mockResolvedValue({ emails: [], total: 0, hasMore: false });
+    const a = makeAccount({ accountId: 'a', mailboxes: [mb('inbox', 'inbox')] }, { advancedSearchEmails });
+
+    await advancedSearchCrossViewEmails([a], 'all', {}, 50, 0);
+
+    const [filter] = advancedSearchEmails.mock.calls[0];
+    expect(filter).toEqual({ inMailbox: 'inbox' });
+  });
+});

lib/unified-mailbox.ts

@@ -465,6 +465,29 @@ export async function searchCrossViewEmails(
     ));
 }
 
+/**
+ * Like `searchCrossViewEmails`, but applies an advanced filter (text + field
+ * conditions from `buildJMAPFilter`, built WITHOUT an `inMailbox` clause) on top
+ * of the cross-view membership. `extraFilter` may be empty ({}), in which case
+ * only the membership filter is used (equivalent to a plain browse).
+ */
+export async function advancedSearchCrossViewEmails(
+  accounts: UnifiedAccountClient[],
+  view: CrossView,
+  extraFilter: Record<string, unknown>,
+  limit: number,
+  position: number,
+): Promise<UnifiedFetchResult> {
+  const hasExtra = Object.keys(extraFilter).length > 0;
+  return fanOutCrossQuery(accounts, (account, jmapAccountId, ids) => {
+    const membership = buildCrossFilter(view, ids);
+    const filter = hasExtra
+      ? { operator: 'AND', conditions: [membership, extraFilter] }
+      : membership;
+    return account.client.advancedSearchEmails(filter, jmapAccountId, limit, position);
+  });
+}
+
 /**
  * Returns the list of unified roles that exist in at least one account's
  * mailboxes.

stores/email-store.ts

@@ -7,7 +7,7 @@ import { useCalendarStore } from "@/stores/calendar-store";
 import { SearchFilters, DEFAULT_SEARCH_FILTERS, buildJMAPFilter, isFilterEmpty } from "@/lib/jmap/search-utils";
 import { emailHooks } from "@/lib/plugin-hooks";
 import type { ExternalSearchResult } from "@/lib/plugin-types";
-import { fetchUnifiedEmails, fetchUnifiedMailboxCounts, searchUnifiedEmails, advancedSearchUnifiedEmails, fetchCrossViewEmails, searchCrossViewEmails, getCrossUnreadTotal, type UnifiedAccountClient, type UnifiedMailboxCounts } from "@/lib/unified-mailbox";
+import { fetchUnifiedEmails, fetchUnifiedMailboxCounts, searchUnifiedEmails, advancedSearchUnifiedEmails, fetchCrossViewEmails, searchCrossViewEmails, advancedSearchCrossViewEmails, getCrossUnreadTotal, type UnifiedAccountClient, type UnifiedMailboxCounts } from "@/lib/unified-mailbox";
 import { useAuthStore } from "@/stores/auth-store";
 import { useAccountStore } from "@/stores/account-store";
 
@@ -959,9 +959,12 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
         const includeGroup = useSettingsStore.getState().includeGroupInUnified;
         const position = emails.length;
         const built = await buildUnifiedAccountClients({ includeGroup });
-        const result = searchQuery
+        const hasFilters = !isFilterEmpty(get().searchFilters);
-          ? await searchCrossViewEmails(built, crossView, searchQuery, emailsPerPage, position)
+        const result = hasFilters
-          : await fetchCrossViewEmails(built, crossView, emailsPerPage, position);
+          ? await advancedSearchCrossViewEmails(built, crossView, buildJMAPFilter(searchQuery, get().searchFilters, undefined), emailsPerPage, position)
+          : searchQuery
+            ? await searchCrossViewEmails(built, crossView, searchQuery, emailsPerPage, position)
+            : await fetchCrossViewEmails(built, crossView, emailsPerPage, position);
         const currentEmails = get().emails;
         const existingIds = new Set(currentEmails.map(e => e.id));
         const newEmails = result.emails.filter(e => !existingIds.has(e.id));
@@ -1796,7 +1799,11 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       if (isUnifiedView && crossView) {
         const includeGroup = useSettingsStore.getState().includeGroupInUnified;
         const built = await buildUnifiedAccountClients({ includeGroup });
-        const result = await searchCrossViewEmails(built, crossView, searchQuery, emailsPerPage, 0);
+        // Cross views apply the advanced filter (text + fields) on top of the
+        // view membership; an empty filter degrades to a plain membership query.
+        const result = await advancedSearchCrossViewEmails(
+          built, crossView, buildJMAPFilter(searchQuery, searchFilters, undefined), emailsPerPage, 0,
+        );
         if (controller.signal.aborted) return;
         const externals = await emailHooks.onProvideSearchResults.transform([] as ExternalSearchResult[], { query: searchQuery, filters: searchFilters });
         set({
@@ -3225,6 +3232,11 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
       selectedMailbox: isScheduledView ? VIRTUAL_SCHEDULED_MAILBOX_ID : leavingScheduled ? "" : state.selectedMailbox,
       selectedEmail: leavingScheduled ? null : state.selectedEmail,
       selectedEmailIds: leavingScheduled ? new Set<string>() : state.selectedEmailIds,
+      // Search is unavailable in the scheduled view (the input is disabled there).
+      // Reset any active search when entering it so a stale query can't linger or
+      // re-run when the user leaves again.
+      searchQuery: isScheduledView ? "" : state.searchQuery,
+      searchFilters: isScheduledView ? { ...DEFAULT_SEARCH_FILTERS } : state.searchFilters,
     };
   }),
   clearPendingUndoSend: () => set({ pendingUndoSend: null }),