Fix: Update twdesk toolsets for desksdkgo v1 + add sparse fieldset support

[ready4god2513]

Patches all twdesk tools to compile against the v1 desksdkgo API, which introduced two breaking changes: Get methods now require a url.Values parameter, and all model string/bool/int fields changed to pointer types.

Adds sparse fieldset support throughout every read operation so the LLM can request only the fields it needs and avoid bloating token counts:

• meta.go: add strPtr/intPtr/boolPtr helpers, sparseFieldsSchema(), getParams() (builds url.Values with includes=all + optional fields), and wire fields into paginationOptions() and setPagination() so every list operation automatically honours the parameter
• All Get tools: accept an optional "fields" array and pass it to the SDK via getParams(); handlers that previously returned text summaries now return full JSON so sparse fields are meaningful
• All List/Search tools: "fields" flows through setPagination to the query string
• files.go, messages.go: fix model field assignments to use pointer types

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Testing

• Tests pass locally (go test -v ./...)
• Added/updated tests for new functionality

Checklist

• Code follows project style guidelines
• Self-reviewed the code
• Added necessary documentation
• No new warnings or errors

[rafaeljusto]

Instead of giving the full sparse field options to the LLM, maybe keep a verbose flag that enables or disables the entire entity? Like, when verbose is disable we could return the ticket id and title only.

[ready4god2513]

This doesn't fix (or make worse) the openai strict mode. I am working on a PR to fix that for Desk right now.

[rafaeljusto]

Instead of giving the full sparse field options to the LLM, maybe keep a verbose flag that enables or disables the entire entity? Like, when verbose is disable we could return the ticket id and title only.

We discussed this, and will go ahead with these changes, monitoring how the LLM behaves with the sparse field options.