Post-merge incident audit-trail & reporting wiring

[JSONbored]

Context

#5137 (Post-merge incident process) bundles engineering — a reporting/audit-trail path — with a policy/legal call (gittensory's actual obligations when an already-merged rented-loop PR is found harmful). Splitting lets the engineering half be contributor-eligible; #5137 itself now covers gittensory's obligations only.

Dependencies

Blocked on #4809's kill-switch/incident-runbook family landing far enough to share an audit-trail convention with (this issue's reporting path is the post-merge counterpart to that pre-merge one).

Requirements

1. Build the reporting path for the case where an already-merged rented-loop PR is later reported as harmful: how a customer or internal operator files the report.
2. Produce a complete, correctly-recorded audit-trail entry for each report.
3. The reporting path must be reachable by both a customer-facing surface and an internal operator surface.
4. Out of scope: defining gittensory's actual obligations (revert assistance, compute credit, notification) — that remains Post-merge incident: loopover's obligations to the customer #5137's own scope, in the same family as Terms of Service & liability terms #4805 (Terms of Service).

Deliverables / Acceptance Criteria

• A working reporting path for an already-merged PR flagged harmful
• A simulated report produces a complete, correctly-recorded audit-trail entry
• The reporting path is reachable by both a customer and an internal operator

Test Coverage Requirements

This PR must ship with full test coverage for every changed line and branch — the repo's Codecov patch gate requires 99%+ coverage. Cover both the customer-initiated and operator-initiated reporting paths, and the resulting audit-trail record shape.

Expected Outcome

The highest-liability scenario named in #4805 (an autonomous agent's merged code found harmful after the fact) has a real, working reporting/audit path — closing the engineering half of the gap #5137 originally covered end to end.

Links & Resources

• Incident runbook for the kill-switch #4809 (the pre-merge kill-switch/runbook this is the post-merge counterpart to)
• Terms of Service & liability terms #4805 (Terms of Service — the same liability family the obligations half of Post-merge incident: loopover's obligations to the customer #5137 belongs to)
• Post-merge incident: loopover's obligations to the customer #5137 (the issue this splits from — now covers gittensory's post-merge obligations only)

[linear-code]

JSO-3886