[P1] Terminalize pre-created background workflow run when PRD lease acquisition fails

[brAperia2025]

Context: CodeRabbit feedback on upstream PR coleam00#1875 surfaced a likely-valid pending-row bug in our fork.

Problem:

• packages/core/src/orchestrator/orchestrator.ts may pre-create a workflow run.
• If acquirePrdExecutionLeaseForRun throws, the function sends an error and returns without terminalizing the pre-created run.

Impact:

• P1. Leaves stale pending rows and can interfere with path locks/status until cleanup.

Acceptance criteria:

• On PRD lease acquisition failure after preCreatedRun exists, mark the run failed/cancelled with a clear guard-blocked reason.
• Log any DB finalization failure separately.
• Add a regression test for lease acquisition failure after pre-creation.

Reference:

• CodeRabbit comment: Merge AISRV Archon state model into dev coleam00/Archon#1875 (comment)