Add system dependencies support for tools

Tools can now declare system-level package dependencies (apt, brew, pacman, dnf)
that get checked and optionally installed when the tool is installed or run.

Features:
- SystemDependency dataclass with short form (string) and long form (dict)
- New system_deps.py module with platform detection and installation
- `cmdforge system-deps <tool>` command to check/install system packages
- `cmdforge check` now shows both CmdForge and system dependencies
- `cmdforge registry install` prompts for system dep installation
- GUI: System Dependencies section in Tool Builder with add/edit dialog
- Runner warns about missing system deps before execution
- Integration with project install (manifest and lock-based)

Also includes:
- Quote paths in wrapper scripts for spaces support
- Tests for value type preservation in code steps
- Unskip invalid tool name test

Co-Authored-By: Claude Opus 4.5 <[email protected]>

tests/test_cli.py

@@ -110,13 +110,14 @@ class TestCreateCommand:
         captured = capsys.readouterr()
         assert 'exists' in captured.err.lower() or 'exists' in captured.out.lower()
 
-    @pytest.mark.skip(reason="CLI does not yet validate tool names - potential enhancement")
     def test_create_invalid_name(self, temp_tools_dir, capsys):
         """Invalid tool name should fail."""
         with patch('sys.argv', ['cmdforge', 'create', 'invalid/name']):
             result = main()
 
         assert result != 0
+        captured = capsys.readouterr()
+        assert 'invalid' in captured.out.lower() or 'invalid' in captured.err.lower()
 
 
 class TestDeleteCommand: