kusto_query: migrate query path/parsing to v2 and add --show-stats

[gholliday]

What does this PR do?

This PR updates the existing kusto_query tool to use Kusto query v2 response handling and adds an optional --show-stats parameter so users can retrieve execution statistics (CPU, memory, cache, extents, network, and cross-cluster breakdown) alongside query results.

It also updates tests and docs for the new behavior, keeps /v1/rest/mgmt unchanged, and adds a changelog entry.

GitHub issue number?

Closes #1786

Pre-merge Checklist

• Required for All PRs
  • Read contribution guidelines
  • PR title clearly describes the change
  • Commit history is clean with descriptive messages (cleanup guide)
  • Added comprehensive tests for new/modified functionality
  • Updated changelog entry under servers/Azure.Mcp.Server/changelog-entries/
• For MCP tool changes:
  • One tool per PR: This PR modifies only kusto_query
  • Updated servers/Azure.Mcp.Server/README.md documentation
  • Validate README.md changes using eng/scripts/Process-PackageReadMe.ps1 (not applicable - README not changed)
  • Updated command list in /servers/Azure.Mcp.Server/docs/azmcp-commands.md
  • Ran ./eng/scripts/Update-AzCommandsMetadata.ps1 to update tool metadata in azmcp-commands.md
  • For modified tool descriptions, ran ToolDescriptionEvaluator with score >= 0.4 and top-3 ranking for related prompts
  • For tools with new names, update consolidated-tools.json (not applicable - no new tool name)
• Extra steps for Azure MCP Server tool changes:
  • Updated test prompts in /servers/Azure.Mcp.Server/docs/e2eTestPrompts.md

Validation run

• dotnet build .\mcp.sln
• ./eng/scripts/Test-Code.ps1 -Paths Kusto
• MCP smoke test over stdio protocol (initialize + tools/list + kusto_query) against https://help.kusto.windows.net with and without show-stats

Invoking Livetests

Copilot submitted PRs are not trustworthy by default. Users with write access to the repo need to validate the contents of this PR before leaving a comment with the text /azp run mcp - pullrequest - live. This will trigger the necessary livetest workflows to complete required validation.

[github-actions]

Thank you for your contribution @gholliday! We will review the pull request and get back to you soon.

[Copilot]

Pull request overview

Updates the kusto_query tool to execute queries via Kusto’s /v2/rest/query frame-based response format and adds an optional --show-stats flag to return structured execution statistics alongside results.

Changes:

• Migrates Kusto query execution to /v2/rest/query and adds v2 frame parsing (PrimaryResult + DataSetCompletion error handling).
• Adds --show-stats option and plumbs statistics extraction from QueryCompletionInformation frames through to the command response.
• Adds/updates unit tests and updates command documentation and changelog entry.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tools/Azure.Mcp.Tools.Kusto/src/Services/KustoService.cs	Adds v2 frame parsing, statistics extraction, and new QueryItemsWithStatisticsAsync APIs.
tools/Azure.Mcp.Tools.Kusto/src/Services/KustoClient.cs	Switches query endpoint to /v2/rest/query, uses named HttpClient, and adds readonly/compression/connection headers.
tools/Azure.Mcp.Tools.Kusto/src/Services/IKustoService.cs	Extends interface with new tuple-returning QueryItemsWithStatisticsAsync overloads.
tools/Azure.Mcp.Tools.Kusto/src/Commands/QueryCommand.cs	Adds --show-stats option and includes optional statistics in the response model.
tools/Azure.Mcp.Tools.Kusto/src/Options/QueryOptions.cs	Adds ShowStats option binding model property.
tools/Azure.Mcp.Tools.Kusto/src/Options/KustoOptionDefinitions.cs	Defines --show-stats option.
tools/Azure.Mcp.Tools.Kusto/src/KustoSetup.cs	Registers a named HttpClient configured for gzip/deflate decompression.
tools/Azure.Mcp.Tools.Kusto/tests/Azure.Mcp.Tools.Kusto.UnitTests/QueryCommandTests.cs	Updates tests to use new service API and adds coverage for --show-stats.
tools/Azure.Mcp.Tools.Kusto/tests/Azure.Mcp.Tools.Kusto.UnitTests/KustoServiceTests.cs	Adds new tests for v2 frame parsing, error handling, and statistics extraction.
tools/Azure.Mcp.Tools.Kusto/tests/Azure.Mcp.Tools.Kusto.UnitTests/KustoClientTests.cs	Adds assertions for v2 endpoint usage and expected request headers.
servers/Azure.Mcp.Server/docs/e2eTestPrompts.md	Adds an e2e prompt that exercises statistics output.
servers/Azure.Mcp.Server/docs/azmcp-commands.md	Documents optional [--show-stats] on kusto query.
servers/Azure.Mcp.Server/changelog-entries/copilot-kusto-query-v2-show-stats.yaml	Changelog entry for v2 migration and the new stats option.

[gholliday]

I can't get the tests working, and it appears that they are a pre-existing issue. I've contributed this to microsoft/fabric-rti-mcp#123 instead, so feel free to close this one.