feat: Add support for tool annotations

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[Copilot]

Pull Request Overview

This PR adds support for tool annotations in the chatlas library, allowing users to provide additional metadata about tools including titles and hints about their behavior. This feature enhances tool usability by providing more context about tool purpose and safety considerations.

Key changes:

• Added annotations parameter to tool registration methods
• Extended ContentToolRequest to include tool reference for accessing annotations
• Automatic annotation propagation from MCP tools

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
chatlas/_tools.py	Added annotations parameter to Tool class and related methods
chatlas/_content.py	Added tool field to ContentToolRequest to enable annotation access
chatlas/_chat.py	Modified tool invocation to populate tool reference in requests
chatlas/init.py	Added model rebuild calls to resolve forward references
tests/test_tool_from_mcp.py	Added test coverage for MCP tool annotation handling
tests/test_content_tools.py	Updated tests to include tool references in requests
tests/conftest.py	Enhanced test assertions to verify annotation functionality
CHANGELOG.md	Documented the new feature

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