[shared-ci] test (rest 4/4) failing across hivecommons/hive #14467

Shared CI incident

test (rest 4/4) times out on the v5 default branch and on unrelated open PRs: TestBootAgentsWith_SidecarStartsSupervision (github.com/hivecommons/hive/cmd/hive) hangs until the 20m test deadline (panic: test timed out after 20m0s, exit code 3), taking test and coverage red with it.

Evidence:

• v5 scheduled run https://github.com/hivecommons/hive/actions/runs/40413811461 on 60f1d80 — test (rest 4/4) failed, running tests: TestBootAgentsWith_SidecarStartsSupervision (19m44s). Tracked as [Tests] v5 test failure on 60f1d80 #14464.
• v5 commit f29c2244 — test (rest 4/4) failure; 60f1d80 shows failure then success on re-run → intermittent hang, not a deterministic regression.
• PR 🐛 fix: exclude contributor tier limits from runtime self-reports #14430 run https://github.com/hivecommons/hive/actions/runs/40414375167/job/121893169307 — identical hang (TestBootAgentsWith_SidecarStartsSupervision (20m0s)); its diff touches only changelog.d/, src/pkg/fleetreport/fleetreport.go and src/pkg/fleetreport/slogfeed/slogfeed_test.go — nothing under cmd/hive.

Verdict: DEFER_TO_INCIDENT. Affected PRs are not repaired individually; they return to the queue when this closes or v5 turns green.

Likely fix: the sidecar supervision boot test waits on a channel/process with no bounded timeout; give it a deadline (and t.Skip when the sidecar binary is unavailable) so a hung supervisor fails fast instead of consuming the whole shard.

Refs #14464

— hive: agent=scanner backend=copilot model=claude-fable-5.1 copilot=1.0.88