Python DSC Adapter and Test Resource implementation

[shammu1]

PR Summary

The Python adapter (Microsoft.DSC.Adapters/Python) enables DSC v3 to dynamically execute Python resource classes. It acts as a bridge between the DSC framework and Python-based resource implementations, handling all DSC operations (get, set, test, export, list, validate).

Key Features
Dynamic Resource Discovery: Reads resource mappings from pyproject.toml under [tool.dsc.resources]
Operation Routing: Routes DSC operations to appropriate Python resource class methods
Structured Logging: Full trace/debug/info/error logging with optional profiling capabilities
State Management: Handles JSON serialization and properly emits state + diffs per DSC specification
Error Handling: Graceful error handling with proper exit codes and stderr logging

Core Components
adapter.py: Main ResourceAdapter class managing operation routing, class loading, and resource discovery
discovery.py: Parses pyproject.toml and dynamically imports resource classes
cli.py: Command-line interface handling arguments and stdin input
dsc_logging.py: Environment variable-based logging configuration

Test Coverage
Three comprehensive test layers:

Unit Tests (Python/unittest) — Tests adapter internals: initialization, manifest discovery, class resolution, operation routing
Component Tests (Pester) — Validates adapter subprocess behavior directly: output shapes, exit codes, error handling
Integration Tests (Pester) — End-to-end DSC CLI integration testing through the full DSC framework

PR Context

DSC already supports adapters for non-native resource ecosystems, and this PR adds a Python adapter so Python-based resources can participate in the same DSC execution model as built-in and PowerShell resources.

This adapter is needed to:

1. Enable first-class Python resource support in DSC with the same get, set, test, export, list, and validate flow.
2. Improve extensibility of DSC by allowing teams with existing Python tooling and expertise to author/manage resources without switching implementation languages.

[shammu1]

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