Support specifying fields to return alongside WIQL query

[kollner]

When calling list_work_items with a WIQL query, any fields included in the SELECT clause beyond the defaults are silently ignored. For example:

SELECT [System.Id], [System.Title], [Microsoft.VSTS.Common.StateChangeDate]
FROM WorkItems
WHERE ...

The StateChangeDate field is not returned in the response. The same applies to System.AreaPath and likely any other non-default field.

Root cause

The Azure DevOps Query By Wiql REST API only returns work item IDs regardless of the SELECT clause. The MCP then fetches full work item details in a follow-up call, but with a hardcoded field list — so the SELECT fields are never forwarded to the item fetch step.

Request

Allow the caller to specify additional fields to include in the follow-up work item fetch, either by:

• Parsing the SELECT clause from the WIQL and forwarding those fields to the batch fetch, or
• Adding an explicit fields parameter to the tool

Impact

Without this, callers cannot retrieve fields like StateChangeDate or AreaPath via a single tool call, forcing multiple round trips or workarounds.

[danhellem]

Duplicate of #976, #419, #397