missing-concurrency

Detects heavy workflows that do not define workflow-level or job-level concurrency.

Why this rule exists:

• stale PR runs often continue after a new commit lands
• that wastes runner minutes and slows the signal people actually care about
• this is especially useful for long-lived AI or agentic PR/comment workflows where stale runs are rarely worth keeping

Current MVP heuristic:

• the workflow is classified as “heavy”
• no top-level concurrency exists
• no job-level concurrency exists

Typical remediation:

• add workflow-level concurrency
• prefer cancel-in-progress: true for PR-oriented CI