feat(utils): Add MCP tool forwarding compatibility tester

[anderscarlssn]

Summary

Adds utils/mcpforwardingtester, a small Python CLI that checks whether the MCP servers you configure for tool forwarding on WorkSpaces Applications will work, before you build a fleet image. It reproduces how the service launches and queries your servers and reports, per server, what passes and what to fix. This catches failures that otherwise only surface after a long image build: a server that lists no tools, a config saved with a BOM, ignored env/cwd, or a tools/list that exceeds the 5 second budget.

What's added

• utils/mcpforwardingtester/: the package, run as py -m mcp_forwarding_tester (or the mcp-forwarding-test command). Two modes: config (validate the deployed config, default path resolved automatically) and server (test a single server ad hoc), with --json output for a build gate and a per-server PASS/WARN/FAIL report.
• Python 3.10+, one runtime dependency (the mcp SDK).
• A README with install and usage.
• Root README.md: added the package to the project structure and a pointer from the tool forwarding section.

Testing

• 19 pytest cases pass: happy path, zero-tools FAIL, missing-executable FAIL, active tool calls, and the latency split.
• Verified end to end on a WorkSpaces Applications Windows Server 2022 image builder: installed from the repo archive in PowerShell and validated a sample config to an OK verdict.
• pyflakes clean; scripts/ci_local.sh passes.

Follow-up

A separate PR will align the existing "MCP redirection" naming across the repo to "MCP tool forwarding."