[air] Report pending compute status consistently in JSON

[caroline-db]

Changes

• Use the task-aware display status for the air list JSON status.
• Add regression coverage that verifies JSON and text both report PENDING while waiting for compute.

Why

The Jobs API reports the parent run as RUNNING before its AIR task has compute. Text output already translates that state to PENDING, so JSON should report the same logical state.

Tests

• go test ./experimental/air/cmd -run ^Test(BuildListRow|DisplayRunStatus)
• ./task checks
• ./task lint (Go lint passed; pinned Ruff 0.15.17 checks run directly because PyPI DNS was unavailable)
• ./task test (10,350 unit tests and 5,258 acceptance tests passed)
• Built the CLI locally and confirmed live runs report PENDING in both formats while waiting for compute and RUNNING in both formats during execution.

This PR was written with Codex.

[eng-dev-ecosystem-bot]

Integration test report

Commit: 93c8389

Run: 35139253044

	Env	✅​pass	🙈​skip	Time
✅​	aws linux	276	15	5:24
✅​	aws windows	278	13	4:14
✅​	azure linux	275	15	6:16
✅​	azure windows	277	13	4:19
✅​	gcp linux	276	15	8:17
✅​	gcp windows	278	13	5:02

Top 3 slowest tests (at least 2 minutes):

duration	env	testname
4:11	aws windows	TestAccept
3:30	gcp windows	TestAccept
3:24	azure windows	TestAccept