feat(keystore,api,ui,docker): encrypted secrets store with a write-only admin page and a secret run helper for the model

ui/src/lib/nav.ts

@@ -20,6 +20,7 @@ export const SYSTEM_PAGES: NavItem[] = [
   { href: "/system/agents", key: "", label: "Agents & endpoints" },
   { href: "/system/jobs", key: "", label: "Jobs" },
   { href: "/system/tokens", key: "", label: "Tokens" },
+  { href: "/system/secrets", key: "", label: "Secrets" },
   { href: "/system/audit", key: "", label: "Audit" },
 ];