#31889 fix(ci): use shared runner state only for the first capacity look

A busy shared document can be read repeatedly while DEV landing placement waits, so the picker never notices a runner becoming idle. The archive picker has the opposite problem: it bypasses the shared reader and always calls the repository runner endpoint, even with its state binding present.

Use the archive document for its first look only, preserving its repository-only registration scope. After a wait, read live. Add an explicit use_state=False option to the shared runner listing and use it for DEV placement after the first look. Missing or invalid documents retain the existing API fallback. In the busy-to-idle regression, DEV placement previously returned no compile after 60 seconds; it now places the compile after the first 30-second recheck.

Follow-up to #31876's Opus review. Its workflow bindings and the five-minute reader age remain in place.

Performance

metric	before	after	delta	harness or run link
routing-App runner-list requests/h at 1000 idle archive picks/h with fresh state	1000	0	-1000 (-100%)	same synthetic idle document through base/head ios_internal_runner.main
time to place a DEV compile when capacity becomes idle at the first recheck	no compile after 60 s	placed at 30 s	restores placement	same busy-document/live-idle main-entrypoint regression with injected clock

Busy rechecks intentionally spend live runner-list requests to observe changed capacity. The table isolates the idle archive path; it does not claim total installation traffic.

Observed / Not run

All 8 archive picker, 23 DEV placement, 11 shared-state reader/scoping, and 7 DEV landing workflow tests pass. Four main-entrypoint regressions fail on test-only commit 837ba603e777 and pass with the fix. They cover idle-state API avoidance, busy-to-idle live recheck, repository-only archive scope, invalid-state fallback and DEV placement after a wait. git diff --check passes. No application build is needed for these picker reads.

Changelog

none

Agent session: agent session

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Summary by cubic

Fixes picker wait loops that kept reusing a stale shared runner-state document, so capacity changes are now noticed after a wait.

• The archive picker reads the shared state document only for its first look; subsequent rechecks read the live runner API.
• DEV placement also uses the shared document only for its first look and rechecks live after waiting.
• Adds a use_state=False option to the shared runner listing for live rechecks.
• Missing or invalid documents keep the existing API fallback.
• The busy-to-idle regression previously placed no compile after 60 seconds; it now places it after the first 30-second recheck.