fix(tui): add no-@token edge case scenario to TDD regression suite

Adds a 5th scenario to tdd_tui_suggestions_query_extraction_4741.feature
that verifies suggestions() is NOT called when the prompt contains no @token.
This covers the guard condition in on_input_submitted and completes the
regression test suite for issue #4741.

features/steps/tdd_tui_suggestions_query_extraction_4741_steps.py

@@ -267,3 +267,13 @@ def step_assert_suggestions_query_4741(
         f"  Got:      '{actual}'\n"
         f"  (The buggy value would have been: '{wrong}')"
     )
+
+
+@then("suggestions was not called for issue 4741")
+def step_assert_suggestions_not_called_4741(context: object) -> None:
+    """Assert that suggestions() was not called (no @token in prompt)."""
+    actual = context._tui4741_captured_query
+    assert actual is None, (
+        f"suggestions() was unexpectedly called with query: '{actual}'. "
+        f"Expected it not to be called when no @token is present in the prompt."
+    )

features/tdd_tui_suggestions_query_extraction_4741.feature

@@ -40,3 +40,11 @@ Feature: TDD: suggestions() query extraction in on_input_submitted uses correct
     And I call on_mount on the app for issue 4741
     And I submit "@actor:local/dev" to the app for issue 4741 and capture the suggestions query
     Then the suggestions query should be "actor:local/dev" not "@actor:local/dev"
+
+  @tdd_issue @tdd_issue_4741
+  Scenario: Prompt with no @token does not call suggestions
+    Given a mock command router and persona state for issue 4741
+    When I instantiate the TUI app for issue 4741
+    And I call on_mount on the app for issue 4741
+    And I submit "analyse the codebase" to the app for issue 4741 and capture the suggestions query
+    Then suggestions was not called for issue 4741