Give the guest setting somewhere to be changed

Reported: no Tools section in Settings. The setting existed in the database and
had no page, which from a person's side is indistinguishable from the feature
not existing.

get_settings_defaults SEEDS a setting. get_settings_cards (ADR-010) is what puts
it in the rail. Declaring only the first is a silent half-feature: nothing fails,
no test notices, and the switch is unreachable.

The page states the cost where the DECISION is made rather than in a document
nobody opens - turn it on and it says a guest-created link records no creator,
so the audit trail can say when and from where but never who.

Admin-only, like every other settings page, because this one decides whether an
unauthenticated caller may write to the site.

Also caught while wiring it: the card asked for a 'shield' icon, which is not in
the settings iconMap, so it would have rendered the fallback puzzle piece - the
glyph that reads as "nobody chose this". Uses wrench, matching Tech Tools.

The row still comes from `flask plugin upgrade-all`; the card appears either
way, and without the row the page loads empty.

plugins/tools/frontend/routes.js

@@ -28,6 +28,14 @@ export default [
     // Browser-only: no API, no data, nothing to protect.
     meta: { plugin: 'tools' }
   },
+  {
+    path: 'settings/secure-send',
+    name: 'secure-send-settings',
+    component: () => import('./views/SecureSendSettings.vue'),
+    // Admin, like every other settings page: this decides whether an
+    // unauthenticated caller may write to the site.
+    meta: { requiresAuth: true, requiresAdmin: true, plugin: 'tools' }
+  },
   {
     path: 'tools/secure-send',
     name: 'tools-secure-send',