types: allow additional properties in tool function schemas

[jonigl]

Summary

This change is part of ollama/ollama#11444 and related to ollama/ollama#11448 where the server simplified ToolFunction.Parameters from a structured schema to json.RawMessage for better flexibility and performance.

Problem: The previous structured approach was limiting JSON schema flexibility and preventing support for advanced tooling scenarios that require complete schema definitions.

What changed

• Added extra='allow' to Tool.Function.Parameters and Property model configurations
• Enables Pydantic models to accept additional fields beyond explicitly defined ones

Why

• Supports complex JSON schemas with custom properties when sending tool definitions to Ollama API
• Resolves validation errors for schemas containing additional fields like validation rules, examples, or vendor extensions
• Improves compatibility with rich tool schema definitions

Related

• Tool Function Parameters Schema Fields Are Being Stripped ollama#11444
• tools: replace structured ToolFunction.Parameters with json.RawMessage ollama#11448