Extend update command error handling and update documentation

- Extend safe_cli_wrapper() to suppress spurious Click errors for both
  install and update commands; add success indicators for update output
- Add test_update_command_error_suppression to verify error suppression
- Expand CLAUDE.md to document all 17 agents with categories
- Add Keep a Contributing-File format header to CONTRIBUTING.md
- Fix TodoFileGuide URL reference in TODO.md
- Add RELEASE_NOTES_v1.0.1.md

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

tests/test_cli_error_handling.py

@@ -37,6 +37,26 @@ class TestClickWorkaround:
                     assert "Got unexpected extra argument" not in stdout_content
                     assert "Got unexpected extra argument" not in stderr_content
 
+    def test_update_command_error_suppression(self):
+        """Test that spurious 'unexpected extra argument' errors are suppressed for update commands."""
+        # Test the update command that also shows spurious errors
+        with patch('sys.argv', ['kaizen-agentic', 'update']):
+            with patch('sys.stdout', new_callable=StringIO) as mock_stdout:
+                with patch('sys.stderr', new_callable=StringIO) as mock_stderr:
+                    try:
+                        safe_cli_wrapper()
+                    except SystemExit:
+                        pass  # Expected for CLI commands
+
+                    stdout_content = mock_stdout.getvalue()
+                    stderr_content = mock_stderr.getvalue()
+
+                    # Should show update message
+                    assert "Updating all installed agents:" in stdout_content
+                    # Should NOT show spurious error message
+                    assert "Got unexpected extra argument" not in stdout_content
+                    assert "Got unexpected extra argument" not in stderr_content
+
     def test_non_install_command_normal_operation(self):
         """Test that non-install commands work normally without interference."""
         with patch('sys.argv', ['kaizen-agentic', 'list']):