Capture a discovered problem, gap, tech debt, or deferred work into a local work queue so a future agent session can pick it up cold. Use mid-session whenever you set work aside instead of doing it now — a fix you judge out of scope for this PR, work that belongs in a follow-up or a separate/later PR, an item you're deferring, or something worth fixing you won't tackle now — so the outstanding item isn't lost without derailing current work; can be called multiple times per session. Trigger phrases: "defer this", "item deferred", "out of scope for this PR", "follow-up work", "leave for another PR", "capture for later", "outstanding item". This skill captures only. Picking a brief back up is the front door's job: worktrail-go <brief-id>.