Wire real PagerDuty alerting into AMS kill-switch trips (currently ledger-only, no paging)

[JSONbored]

Problem

packages/loopover-engine/src/governor/kill-switch.ts and packages/loopover-miner/lib/governor-kill-switch.ts contain no notify/alert/PagerDuty hook of any kind — a kill-switch trip is only ever a governor-ledger row. apps/loopover-ui/content/docs/ams-kill-switch-incident.mdx's own Detection section assumes a human is "already on the page" before its 15-minute response target starts — there is no automated paging that would actually get a human there.

Area

packages/loopover-engine/src/governor/, packages/loopover-miner/lib/governor-kill-switch.ts, src/services/notify-pagerduty.ts.

Proposal

Wire a real notify/page hook into the kill-switch trip path.

⚠️ Required pattern — read src/services/notify-pagerduty.ts before starting. Reuse it exactly (dedup-key coalescing, severity floor, cooldown window) — do not build a second alerting mechanism or call PagerDuty's API directly from the kill-switch code.

Deliverables

• A kill-switch trip calls notify-pagerduty.ts's existing integration, not a new one.

Test Coverage Requirements

packages/loopover-engine/**, packages/loopover-miner/** — match each package's existing test conventions for the kill-switch modules; mock the PagerDuty call, no live paging in tests.

Resources

• packages/loopover-engine/src/governor/kill-switch.ts, packages/loopover-miner/lib/governor-kill-switch.ts
• src/services/notify-pagerduty.ts (the required pattern)
• apps/loopover-ui/content/docs/ams-kill-switch-incident.mdx (the runbook this closes the gap for)

Boundaries

Extends the existing alerting pattern only.

Contributor-eligible. Reuse notify-pagerduty.ts exactly — a PR that builds a new alerting path does not satisfy this issue.

[linear-code]

JSO-5416