Harden cursor overlay rendering failures

[enaboapps]

What changed

• contain cursor overlay drawing failures on the overlay thread and disable only overlay rendering for the process
• stop follow and animation work after failure and emit one sanitized runtime diagnostic
• cap animation near 30 FPS and avoid invalid or empty repeat arcs
• guarantee cleanup for partially acquired native drawing resources
• cover repeat arc bounds and one-shot OutOfMemoryException containment

Root cause

GDI+ surfaced resource exhaustion as OutOfMemoryException from the repeat progress arc. Cursor overlay callbacks were unguarded, so the exception escaped the WinForms message loop and opened the JIT crash dialog.

Impact

Mouse, keyboard, Bluetooth, and command processing continue if the optional cursor overlay fails. The overlay remains disabled until app restart to avoid an allocation retry loop.

Validation

• focused cursor overlay tests: 28 passed
• 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 (433 unit tests and 1 integration test passed)

Closes #429