feat(sync): add View log button to sync error banner

When a sync failure banner appears in the email list screen, a new
'View log' button navigates directly to the account's sync log screen
so the user can see the full error details.

Also creates issue #75 for the first-snooze-in-new-account failure.

Closes #13

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

lib/ui/screens/email_list_screen.dart

@@ -373,6 +373,12 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
           },
           child: const Text('Retry'),
         ),
+        TextButton(
+          onPressed: () => context.push(
+            '/accounts/${widget.accountId}/sync-log',
+          ),
+          child: const Text('View log'),
+        ),
         TextButton(
           onPressed: () => setState(() => _dismissedError = error),
           child: const Text('Dismiss'),

test/unit/account_sync_manager_test.mocks.dart

@@ -472,6 +472,25 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
         returnValue: _i4.Future<List<_i2.Email>>.value(<_i2.Email>[]),
       ) as _i4.Future<List<_i2.Email>>);
 
+  @override
+  _i4.Future<List<_i2.EmailAddress>> searchAddresses(
+    String? accountId,
+    String? query, {
+    int? limit = 10,
+  }) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #searchAddresses,
+          [
+            accountId,
+            query,
+          ],
+          {#limit: limit},
+        ),
+        returnValue:
+            _i4.Future<List<_i2.EmailAddress>>.value(<_i2.EmailAddress>[]),
+      ) as _i4.Future<List<_i2.EmailAddress>>);
+
   @override
   _i4.Future<int> flushPendingChanges(
     String? accountId,

test/unit/undo_service_test.mocks.dart

@@ -332,6 +332,25 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
         returnValue: _i4.Future<List<_i2.Email>>.value(<_i2.Email>[]),
       ) as _i4.Future<List<_i2.Email>>);
 
+  @override
+  _i4.Future<List<_i2.EmailAddress>> searchAddresses(
+    String? accountId,
+    String? query, {
+    int? limit = 10,
+  }) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #searchAddresses,
+          [
+            accountId,
+            query,
+          ],
+          {#limit: limit},
+        ),
+        returnValue:
+            _i4.Future<List<_i2.EmailAddress>>.value(<_i2.EmailAddress>[]),
+      ) as _i4.Future<List<_i2.EmailAddress>>);
+
   @override
   _i4.Future<int> flushPendingChanges(
     String? accountId,