fix: Update terminal detection tests for headless mode default

The terminal detection tests were failing because they expected the old
terminal mode behavior, but headless mode is now the default.

Fix:
- Add headless=False parameter to all terminal detection tests
- Tests now explicitly test interactive (terminal) mode
- test_subprocess_popen_called_with_correct_args: Tests terminal launch
- test_terminal_launch_error_handling: Tests error handling
- test_output_message_unknown_terminal: Tests warning messages

These tests only run on macOS (they're skipped on Linux) and test the
interactive terminal launch functionality, so they need headless=False.

Impact:
- All 3 failing macOS tests should now pass
- 391 tests passing on Linux
- CI should pass on macOS now

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

tests/test_terminal_detection.py

@@ -164,9 +164,9 @@ class TestDetectTerminalApp(unittest.TestCase):
             # Mock Popen to prevent actual terminal launch
             mock_popen.return_value = MagicMock()
 
-            # Run enhancer
+            # Run enhancer in interactive mode (not headless)
             enhancer = LocalSkillEnhancer(skill_dir)
-            result = enhancer.run()
+            result = enhancer.run(headless=False)
 
             # Verify Popen was called
             self.assertTrue(mock_popen.called)
@@ -239,7 +239,8 @@ class TestDetectTerminalApp(unittest.TestCase):
             old_stdout = sys.stdout
             sys.stdout = captured_output
 
-            result = enhancer.run()
+            # Run in interactive mode (not headless) to test terminal launch
+            result = enhancer.run(headless=False)
 
             # Restore stdout
             sys.stdout = old_stdout
@@ -279,7 +280,8 @@ class TestDetectTerminalApp(unittest.TestCase):
             # Mock Popen to prevent actual launch
             with patch('subprocess.Popen') as mock_popen:
                 mock_popen.return_value = MagicMock()
-                enhancer.run()
+                # Run in interactive mode (not headless) to test terminal detection
+                enhancer.run(headless=False)
 
             # Restore stdout
             sys.stdout = old_stdout