chat/tools refactor #8

[x2d7]

Pull request for #8

Changes

Data Control changes:

• Unexported fields and types that should not be used externally (ToolFunction, Func, Tool.Schema access controlled via GetSchema).

Tools changes:

• Replaced slice-based storage in Tools with a map to allow efficient Add/Remove operations and to prevent duplicate Tool IDs.
• Added support for functional options in Tools.Add to customize Tool IDs.
• Enhanced snapshot logic to correctly populate Tool IDs and skip duplicate checks when auto-increment is enabled.

Tool Schema changes:

• Introduced support for primitive input types in tools in addition to struct types.
• Extracted schema generation logic into a separate schema.go for better separation of concerns.

Minor changes:

• Renamed Tool.Name field to Id for clarity and consistency.

---

Testing

No tests included, since the testing workflow will be added after issue #3 will be merged into dev.