Add 20 BATS tests and 1 interactive test for v0.5.0 edge-case
fixes. FIDO2 keygen now prompts to retry on "device not found"
instead of exiting. Remove stale Qubes vhci_hcd warning. Update
hardware test matrix in README.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
