Runtime capability metadata claims Python and Go are available when they are not

[mcodilla]

Describe the bug

The PowerShell tool documentation states that Python, Node.js, and Go can be run with python, node, and go. In this environment, Node.js was available, go was absent, and python resolved only to the Windows Store application-execution alias rather than an installed interpreter.

Affected version

1.0.89-7

Steps to reproduce the behavior

1. Start Copilot CLI on the environment described above.

2. Ask it to run:

   python -c "print('hello')"

3. Optionally inspect the advertised commands:

   Get-Command python,node,go -ErrorAction SilentlyContinue

Expected behavior

Either:

• Python and Go are installed and runnable as advertised, or
• Tool capability metadata accurately reports which runtimes are available.

Actual result

Python failed with exit code 9009:

Python was not found; run without arguments to install from the Microsoft Store,
or disable this shortcut from Settings > Apps > Advanced app settings >
App execution aliases.

Get-Command showed:

Python : C:\Users\mcodilla\AppData\Local\Microsoft\WindowsApps\python.exe
Node   : C:\Program Files\nodejs\node.exe
Go     :

### Additional context

The mismatch caused a YAML validation attempt to fail even though the tool contract explicitly said Python could be used. Capability detection should reject Windows Store aliases that do not resolve to an installed runtime.