fix: offer every folder as a tree in the search folder picker instead of the first twelve

src/lib/__tests__/search-scope-folders.test.ts

@@ -0,0 +1,30 @@
+import { describe, it, expect } from 'vitest';
+import fs from 'node:fs';
+import path from 'node:path';
+import { searchScopeFolders } from '../search-scope-folders';
+import type { Mailbox } from '../../api/types';
+
+// The search panel's Folder picker was a flat list cut at twelve folders, so
+// deeper or later folders couldn't be searched on their own (webmail
+// lib/search-scope-folders.ts lists them all as a tree).
+
+const box = (id: string, parentId: string | null = null, role: string | null = null) =>
+  ({ id, name: id, parentId, role, sortOrder: 0, totalEmails: 0, unreadEmails: 0, isShared: false } as unknown as Mailbox);
+
+describe('search folder picker', () => {
+  it('lists every folder, each subfolder after its parent with its depth, without the open one', () => {
+    const boxes = [box('inbox', null, 'inbox'), ...Array.from({ length: 15 }, (_, i) => box(`f${String(i).padStart(2, '0')}`)), box('child', 'f03')];
+    const list = searchScopeFolders(boxes, 'inbox');
+    expect(list).toHaveLength(16);
+    const ids = list.map((m) => m.id);
+    expect(ids.indexOf('child')).toBe(ids.indexOf('f03') + 1);
+    expect(list.find((m) => m.id === 'child')?.depth).toBe(1);
+    expect(ids).not.toContain('inbox');
+  });
+
+  it('is what the panel shows, uncut', () => {
+    const list = fs.readFileSync(path.resolve(__dirname, '../../screens/EmailListScreen.tsx'), 'utf8');
+    expect(list).not.toMatch(/\.slice\(0, 12\)/);
+    expect(list).toMatch(/searchScopeFolders\(scopedMailboxes, currentMailboxId\)\.map/);
+  });
+});

src/lib/search-scope-folders.ts

@@ -0,0 +1,22 @@
+import type { Mailbox } from '../api/types';
+import { buildMailboxTree, flattenVisible, type MailboxNode } from './mailbox-tree';
+
+/**
+ * The folders the search panel's Folder picker offers: every folder (it was
+ * cut at twelve), in sidebar order with each subfolder right after its parent
+ * and its `depth` for indenting (webmail lib/search-scope-folders.ts). The
+ * open folder is left out: "This folder" picks it. A shared account's
+ * grouping row is no folder and is left out too.
+ */
+export function searchScopeFolders(mailboxes: Mailbox[], currentMailboxId: string | null): MailboxNode[] {
+  const tree = buildMailboxTree(mailboxes);
+  const all = new Set<string>();
+  const collect = (nodes: MailboxNode[]) => {
+    for (const n of nodes) {
+      all.add(n.id);
+      collect(n.children);
+    }
+  };
+  collect(tree);
+  return flattenVisible(tree, all).filter((n) => !n.isAccountNode && n.id !== currentMailboxId);
+}

src/screens/EmailListScreen.tsx

@@ -64,6 +64,7 @@ import { isPermanentDelete, confirmPermanentDelete } from '../lib/delete-confirm
 import { confirmMailRemoval } from '../lib/mail-removal-confirm';
 import { moveSheetCurrentId } from '../lib/move-targets';
 import { listViewKey } from '../lib/list-view-key';
+import { searchScopeFolders } from '../lib/search-scope-folders';
 import { draftContextFromEmail, isDraftEmail } from '../lib/draft-context';
 import { getFullEmail, emptyMailbox as apiEmptyMailbox } from '../api/email';
 import type { RootStackParamList } from '../navigation/types';
@@ -1854,17 +1855,18 @@ export default function EmailListScreen({
                         active={folderScope === 'current'}
                         onPress={() => setFolderScope('current')}
                       />
-                      {scopedMailboxes
+                    </View>
-                        .filter((m) => m.id !== currentMailboxId)
+                    {/* Every folder, as a tree (it was a flat list cut at 12). */}
-                        .slice(0, 12)
+                    <View style={styles.scopeFolderList}>
-                        .map((m) => (
+                      {searchScopeFolders(scopedMailboxes, currentMailboxId).map((m) => (
+                        <View key={m.id} style={{ marginLeft: m.depth * spacing.lg }}>
                           <ScopeChip
-                            key={m.id}
                             label={localizeMailboxName(m.role, m.name, t)}
                             active={folderScope === m.id}
                             onPress={() => setFolderScope(m.id)}
                           />
-                        ))}
+                        </View>
+                      ))}
                     </View>
                   </View>
 
@@ -2427,6 +2429,7 @@ function makeStyles(c: ThemePalette) {
     gap: spacing.sm,
     marginTop: 4,
   },
+  scopeFolderList: { alignItems: 'flex-start', gap: spacing.xs, marginTop: spacing.sm },
   triToggle: {
     flexDirection: 'row',
     alignItems: 'center',