Support Apple container CLI 1.5.0

[joeshirey]

Adds support for container 1.5.0 and keeps 1.4.1 supported.

What changed

• Fixtures: Added sanitized JSON captured from the 1.5.0 CLI under src/test/fixtures/container-1.5.0/, covering system status, containers, stats, images, machines, volumes, networks, and builder.
• Tests: The frontend compatibility test finds every container-* fixture set and runs once per set. The stats, builder, system-status, and recreation tests now check both 1.4.1 and 1.5.0.
• Live smoke test: Renamed live_1_4_1_smoke to live_smoke. It accepts any version in SUPPORTED_VERSIONS.
• Docs: Renamed docs/container-1.4.1.md to docs/container-1.5.0.md and added a 1.5.0 section. Updated the README and the CI comment.

Findings

• The app code didn't need changes. For the resources the app reads, the JSON from 1.5.0 has the same key structure as 1.4.1.
• The only breaking CLI change in 1.5.0 removes container k8s start. The app doesn't use Kubernetes.
• Unknown commands still exit nonzero (exit code 64 in 1.5.0), so the error path works as before.
• image ls lists every platform variant. The app still shows the arm64 size.
• The upstream problem where the first machine run after machine create fails is still present in 1.5.0. I reproduced Operation not supported by device. The smoke test's workaround stays.

Validation

Run on Apple silicon, macOS 27.0, container 1.5.0, after rebasing onto current main (Vitest 5):

• npm test: 303 passed
• npm run build, cargo fmt --check, cargo clippy -D warnings, cargo build: pass
• cargo test: 117 passed, with 1 test ignored (the live smoke test)
• cargo test --test cli_compatibility live_smoke -- --ignored: passed against 1.5.0, and no acd-smoke- resources were left behind

Not tested: the system status not-running and unregistered paths. Testing them would mean stopping the local container service.