GRM-58: refactor: require tea CLI everywhere, fail on missing Vikunja task

tests/unit/test_setup.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 from pathlib import Path
 from unittest.mock import patch
 
+import click
 import pytest
 from click.testing import CliRunner
 
@@ -81,10 +82,12 @@ class TestVerify:
 
 
 class TestConfigureTeaLogin:
-    def test_tea_not_installed(self) -> None:
+    def test_tea_not_installed_raises(self) -> None:
+        """tea must be installed — setup fails if it's missing."""
         with patch("shutil.which", return_value=None):
             with patch.dict("os.environ", {"REPO_TOKEN": "tok"}, clear=True):
-                setup._configure_tea_login()
+                with pytest.raises(click.ClickException, match="not installed"):
+                    setup._configure_tea_login()
 
     def test_no_repo_token(self) -> None:
         with patch("shutil.which", return_value="/usr/bin/tea"):