v1.5.0 - Crash hardening and logging

Fixes app crashing when pressing Ask. Adds a global exception handler that logs unhandled errors to %LOCALAPPDATA%\ExcelSpiritInside\logs\app.log and shows a message instead of terminating. Inference is now hardened for the CPU backend (GpuLayerCount=0, thread cap, extra anti-prompts) with step-by-step logging. Requires .NET 10 Desktop Runtime (win-x64).