feat: add 'All accounts' entry to FolderDrawer for back-navigation

Users had no obvious way to return to the account list after opening an
account. Adding an 'All accounts' tile at the top of the drawer (visible in
both MailboxListScreen and EmailListScreen) lets users navigate to /accounts
from anywhere inside an account.

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

done.md

@@ -6,6 +6,13 @@ Tasks get moved from next.md to done.md
 
 ## Tasks
 
+## Navigate back to account list from inside an account
+
+Added an "All accounts" tile (with `Icons.switch_account`) at the top of `FolderDrawer`,
+above a divider and the folder list. Tapping it closes the drawer and navigates to
+`/accounts` via `context.go`. The drawer is shown in both `MailboxListScreen` and
+`EmailListScreen`, so this entry point is reachable from anywhere inside an account.
+
 ## Speed up `task deploy-android`
 
 Two parallelism improvements:

lib/ui/widgets/folder_drawer.dart

@@ -74,6 +74,15 @@ class FolderDrawer extends ConsumerWidget {
               ),
             ),
           ),
+          ListTile(
+            leading: const Icon(Icons.switch_account),
+            title: const Text('All accounts'),
+            onTap: () {
+              Navigator.pop(context);
+              context.go('/accounts');
+            },
+          ),
+          const Divider(height: 1),
           Expanded(
             child: StreamBuilder(
               stream: mailboxRepo.observeMailboxes(accountId),

next.md

@@ -18,12 +18,6 @@ Then commit.
 
 ## Tasks
 
-I opened an account. How to get back to the list of accounts?
-
-I saw no way to do that.
-
----
-
 I opened a mailbox. I search for "foo bar". I want to see all mails containing foo and bar. Not
 mails containing "foo bar" exactly.