#1061 Live checkers out of date after #1041/#1013/#977: retarget or delete stale probes

EARS SPEC: - Every live checker named in SPECS/deploy-first-ci-build.md step 5 shall probe only routes the served API exposes, and shall parse error bodies as JSON. - Each retargeted check shall be shown red against a sabotaged or old deploy and green on the current one. EVIDENCE (#1056 run, 2026-10-23 ~23:00Z): - verify_973_975_989/run.py call() returns {'raw': text} on HTTP errors, so error.code is always empty: #975 and #1003submit can never pass (served responses match expected code and message). - check_911_exception_text.py, verify_api_input/check_live.py (29 cases), verify_tenant_isolation/check_1014_1015.py (name/version route): probe routes removed by #1041 (404). - verify_976_958/check_health.py: /workers is platform-only since #1013; #996 expects 403 FORBIDDEN_TOOLS but contract is 400 WORKFLOW_VALIDATION_ERROR (asserted by verify_1005). - #974 condition-chain fixtures reference the unselected branch's output in 'after'; #977 now fails missing paths. Needs a decision: fix fixture or define a skipped task's result. - #967 case 6: executor re-enters wait_branches before risky, so no branch is sleeping when the run fails; live teardown path not exercised (scratch-DB teardown 23/23). - verify_966_967 has no live checker script; the agent wrote /var/tmp/hw-verify/check_966_967_live.py (31/2). Adopt into the repo. - scripts/demo submit/validate_demo_workflow_tools.py: predates #944, hardcodes race_cancelled: 2 (can't fail), writes inside the live container; rewrite or delete under #944/#961. SYNTHESIS: test maintenance; concept = checkers track the served contract; red/green per check.