Fixes
- `trcc detect` showed "No device path found" for LED controllers (#90): LED protocol devices now display `vid:pid` path correctly
- `trcc test` crashed on LED-only devices (#90): now exits cleanly with a message directing to `trcc led`
- `trcc report` was blind to LED devices (#90): LED devices were silently skipped in the Handshakes section — now fully included
Internal
- Extract `TrccApp` god class: all inline handler closures → `core/handlers/` package
- Fix hexagonal violation in `OSCommandHandler`: theme download callables injected at construction
- Python 3.10 compatibility: `TypeAlias`, remove `@override`, ruff `target-version = py310`