feat(events): enablement, per-run caps and mayInvoke (Phase 6)

Two new tables — event_action_settings (the deployment switchboard) and
event_run_budget (what a run has spent and the most it may) — plus verified_at
and verified_by on event_versions. The whole authorisation decision moves behind
one function, events/authorize.js: role, enablement, cap, and the shard's own
switch named as the layer core deliberately does not duplicate.

Three routes, none moved: GET/PUT /admin/events/actions (admin in both
directions) and POST /admin/events/:id/verify (admin, editor — a dry run
dispatches nothing).

Four decisions, settled by the org lead 2026-09-03:

- The default-off line falls between inspect and change, not between notify and
  inspect. Read literally, §K shipped core.wait disabled. The same line is the
  role floor.
- The tightest cap wins where two actions spend one dimension, pinned into the
  run at creation with the action it came from.
- A refusal follows the step's on_failure and takes health to degraded — its own
  status and its own log kind, because a refusal is not an outage.
- The verify gate is enforced for scheduled starts only: a human pressing Start
  now is the review the gate exists to require.

Derived and flagged for review: a dry run fails rather than warns on a disabled
action or an over-cap plan, and the unattended path does not re-check the
starter's role.

+111 tests (1921/1847/73/1 — the one failure pre-existing and environmental),
including a 403 walk over the real router and two concurrent spends against one
cap on a real MariaDB. The live walk found two defects, both fixed here: the run
console route dropped the budget it was handed, and the role refusal used a
plural verb over a one-item list.

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01T6t8mrAWhZU5vnyYgZTMtL

client/src/routes/admin/AdminLayout.jsx

@@ -137,6 +137,11 @@ export const NAV = [
       // and the arcs it manages are authoring gated on the buttons rather than
       // on the row.
       { to: '/admin/events/calendar', label: 'Calendar', icon: IconCalendar, roles: ['admin', 'editor', 'moderator'] },
+      // Phase 6, and the one row in this group that is NOT staff-wide. §K puts
+      // the switchboard in the same row as the world-changing actions it
+      // governs: what a deployment permits at all is configuration, not a read,
+      // and the server gates both the GET and the PUT on `admin`.
+      { to: '/admin/events/actions', label: 'Actions', icon: IconGear, roles: ['admin'] },
     ],
   },
   {
@@ -223,6 +228,7 @@ const TITLES = {
   '/admin/engagement/retention': 'Retention',
   '/admin/events': 'Events',
   '/admin/events/calendar': 'Event calendar',
+  '/admin/events/actions': 'Event actions',
   '/admin/events/new': 'New event',
 }