feat(pr-pipeline): write the lane record into pr-unblock check-run annotations and lane.json #7765

Refs: #7737

What to build

The lane record producer (component C1 of the automation-lanes never-block design). #7737 added readers for a usage-limit stop; nothing writes what they read yet, so they are inert:

• pr-run-activity-write.yml must run ci-workflows report-lane-outcome (or an equivalent step) and put its lane record into the annotations of the posted pr-unblock check run. Today the check run carries only an output title and summary.
• For the issue lane, the same record's class and resets must reach lane.json. The Collect the issue outcome step rewrites lane.json to {"branch":""} when the keep step did not succeed, so it must keep the class there.
• class and resets come only from the runner's lane record, never from the model-writable work-outcome.json: a run that could write them could forge a limit stop and set its own restart time.

Consumers

• .github/scripts/pr-unblock/limit-stop.mjs (limitResetsAt, read by dispatch.mjs and feedback-dispatch.mjs): the check-run annotation.
• .github/scripts/work-resolve-issue/report-outcome.mjs (readLimit, the limited exit): lane.json.
• .github/scripts/work-unblock/label-unblocked.mjs restarts on the limited marker that exit posts.

Done when

A limit-stopped pr-unblock run and a limit-stopped work-resolve-issue run each produce the record those readers parse, shown by a test or a live run.