Bootable 0.1.2: Omarchy client progress and virtual USB UEFI test

[debpalash]

Outcome

• adds an explicit --json-progress client mode to bootable write
• routes CLI writes through Bootable’s narrow privileged helper and revalidation path
• streams stable progress/finished/failed NDJSON events for trusted clients
• adds a disposable Bootable write → byte verification → QEMU USB → OVMF assertion
• detects Ubuntu and Arch OVMF layouts and uploads both UEFI frames
• bumps the RC package version to 0.1.2

Safety

• no target is ever selected implicitly
• fixed, system, read-only, and non-removable disk protections are unchanged
• the virtual write harness accepts only a freshly created /dev/loopN, while normal discovery still excludes loops
• QEMU attaches the detached backing file read-only as removable USB

Validation

• cargo fmt --all --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test --workspace
• local disposable virtual-USB write and OVMF boot assertion: RGB 1,0,171 matched #0000aa ±64/channel