Smoke

Build, import, and compute-backend resolution

4/4 passed in 348ms

Test	What it does	Result
test_backend_resolves	A compute backend resolves without error and reports name/precision/device.	✅ pass
test_supports_rejects_unknown_precision	supports() raises on anything that is not f32/f64.	✅ pass
test_supports_tracks_precision	supports() agrees with the reported precision, and f32 is always available.	✅ pass
test_version	qkd.__version__ comes from the Rust crate and agrees with all three declaration sites, so a two-of-three bump fails here rather than shipping.	✅ pass