feat(mail): return exact messages from Quick Access

tests/test_manifest.py

@@ -9,6 +9,15 @@ from govoplan_mail.backend.manifest import _mail_retirement_provider, get_manife
 
 
 class MailManifestTests(unittest.TestCase):
+    def test_mail_quick_access_can_return_exact_message_references(self) -> None:
+        frontend = get_manifest().frontend
+        self.assertIsNotNone(frontend)
+        tool = next(
+            item for item in frontend.quick_access_tools if item.id == "mail.messages"  # type: ignore[union-attr]
+        )
+        self.assertIn("select", tool.modes)
+        self.assertEqual(("mail.message",), tool.returned_reference_kinds)
+
     def test_manifest_declares_optional_addresses_lookup(self) -> None:
         manifest = get_manifest()