Fix: to_gemini_tool to return types.Tool object. Fixes #223

[Areen-09]

Description

This PR resolves an issue (#223) where SkillLoader.to_gemini_tool() was returning a plain dictionary instead of a proper types.Tool object. The google-genai SDK expects a types.Tool instance inside GenerateContentConfig(tools=...), which caused runtime failures when developers passed the output of to_gemini_tool() directly into their Gemini generation config, as shown in our documentation and some examples.

Changes introduced:

• Framework (skillware/core/loader.py): SkillLoader.to_gemini_tool() now correctly imports google.genai and constructs/returns a types.Tool object instead of a raw dictionary.
• Examples: Removed the manual types.Tool wrapping from all Gemini examples (gemini_uk_companies_house_handler.py, gemini_issue_resolver.py, etc.). Additionally, all Gemini examples now consistently use SkillLoader._sanitize_function_tool_name(bundle["manifest"]["name"]) for deriving tool names safely.
• Tests (tests/test_loader.py): Updated the test assertions for test_to_gemini_tool to inspect the nested Protobuf structures of the types.Tool object (tool.function_declarations[0]).
• Documentation: Updated docs/usage/gemini.md to clarify that to_gemini_tool() automatically handles this object instantiation for the developer.
• Changelog: Added a Fixed entry under [Unreleased] detailing the framework breaking fix.

Type of Change (Matches Issue Templates)

• Skill Proposal: New Skill (Contains manifest.yaml, skill.py, and instructions.md)
• Bug Report Fix: Non-breaking change which fixes an execution error or framework bug
• Doc Fix: Documentation Update
• Framework Feature / RFC Updates: Core Framework Update (Changes to base_skill.py, loader.py, etc.)

Checklist (all PRs)

• My code follows the Agent Code of Conduct.
• I have run python -m flake8 ., pytest skills/ (or skillware test), and pytest tests/ locally (or the subset relevant to this change).
• CHANGELOG.md updated under [Unreleased] if this PR changes user-visible behavior.
• examples/README.md is updated if this PR adds, renames, or removes a runnable script under examples/.

Related Issues

Fixes #223

[rosspeili]

Thanks @Areen-09, this is a solid fix.

LGTM on the loader + examples + tests. to_gemini_tool() returning types.Tool with sanitized names matches what google-genai expects, and the example dispatch updates look right. Tests pass locally.

Before merge:

• Update Gemini snippets in docs/skills/issue_resolver.md, token_limiter.md, and uk_companies_house_handler.md, they still show manual types.Tool wrapping / dict mutation, which will break now that the loader returns types.Tool.
• Fix docs/introduction.md, Gemini tool names are sanitized like OpenAI, not raw category/skill_name.
• Maybe add a test_to_gemini_tool case for slash sanitization, note API return-type change under Changed in CHANGELOG.

Happy to merge once those doc bits are in, core work looks good. <3