Fix PC Switch Control status text colour

[enaboapps]

Summary

• bind the active PC Switch Control profile status to the current theme text colour
• add a stable automation identifier for the status element
• cover light, dark, active, and inactive rendering states

Root cause

The status TextBlock did not declare a foreground, so WPF inherited its default black text instead of the dynamic theme resource.

Validation

• dotnet restore src/SwitchifyPc.sln
• dotnet build src/SwitchifyPc.sln -c Release --no-restore (0 warnings, 0 errors)
• dotnet test src/SwitchifyPc.sln -c Release --no-build (522 unit, 1 integration)
• focused light/dark WPF regression tests (2 passed)
• live inactive state confirmed hidden without changing protocol or profile data

Closes #481