daily-fix: adopted failover clears runpod-wedge sentinel

Overview / Motivation

Auto-filed by /daily 2026-07-24 problem sweep (session dd0af0ae, task #1586).

Goal

When an owning session ADOPTS a replacement pod after a wedge-failover, the poll/tick lane must resume reading live state instead of returning terminal-wedge forever.

Workflow gap

• Bug observed: after the 05:33Z wedge-failover on #1586, tick_triage returned verdict dead terminal_runpod_wedge_already_handled (log_age 1000000000, pid False) on consecutive ticks (2 firings, 07:05Z and 07:37Z) while the adopted relaunch-7 run was demonstrably alive; the poller never drained the results sentinel (10:31Z marker: "the wedge-blinded poller could not drain it") and the orchestrator vetoed + hand-rolled direct-SSH 30-min ticks for the rest of the run.
• Why it is a workflow gap: the _runpod_wedge_already_handled idempotency guard (correct for preventing a second terminate) has no adoption escape — a NEWER epm:run-launched / rewritten handle should flip the lane back to live polling.
• Confidence (emitter): high.
• verified-at-filing: grep -rn 'already_handled' scripts/backend_poll.py → _runpod_wedge_already_handled def at backend_poll.py:1917, reason mint runpod_wedge_already_handled at :2196, sentinel lifecycle :1828-2239 (7 hits, 2026-07-25); grep -n 'wedge' scripts/tick_triage.py → no sentinel-name hits (tick consumes the poll-lane verdict; primary target is backend_poll.py, tick_triage.py secondary for the verdict pathway).

Proposed change (candidate diff sketch — refine in planning)

In _runpod_wedge_already_handled (scripts/backend_poll.py:1917): return False (and best-effort clear the sentinel) when the issue carries an epm:run-launched marker — or a handle rewrite — NEWER than the sentinel's mtime/payload ts (the adoption signal). Add a pin test.

Scope / surfaces

• Primary target: scripts/backend_poll.py (+ scripts/tick_triage.py only if the verdict pathway needs a matching change)

Constraints / invariants

• Workflow-surface only — never experiment code, configs/, or tasks/.
• scripts/workflow_lint.py no-flags run passes; ruff on touched files passes.
• This session runs under a workflow_fix_target: Provenance line — recursion guard applies.

Provenance

• fingerprint: b5fa568aa03d

• workflow_fix_target: scripts/backend_poll.py