[Feat]: Add standard testing scaffolding to the python_skill template

[rosspeili]

Feature Description

The standard skill generation template in templates/python_skill/ contains a boilerplate skill.py and manifest.yaml, but actively lacks any testing scaffolding. To ensure high-quality community contributions, we must encourage Test-Driven Development (TDD) by default.

Rationale

Without a baseline testing file, contributors are less likely to write tests for their skills before submitting pull requests. A standard boilerplate will significantly speed up the PR review process and ensure skill reliability.

Implementation Idea

1. Add a stub test_skill.py into the templates/python_skill/ directory.
2. Utilize pytest to provide a mock execution context for the boilerplate 'weather' or 'hello world' capability.
3. Ensure the boilerplate test includes assertions that validate the skill's return object strictly matches the output schema defined in its manifest.yaml.