Adopt @simpleworkjs/frontend's messages/modal/validate modules

Replaces the vendored app.util.actionMessage/actionConfirm/alert (the
latter added ad hoc to fix "app.util.alert is not a function") with the
published @simpleworkjs/frontend package: app.messages.action/confirm,
app.modal.open, and app.validate.js (which also replaces the identical
vendored val.js). Gains real HTML-escaping on message content and a toast
fallback when there's no inline .actionMessage target, neither of which
the vendored code had.

app.api/app.auth/app.pubsub/app.socket in app-base.js are untouched —
they're app-specific (dual-mode callback/promise API, auth-token header
injection) and not something the generic frontend package's app.js
provides, so it isn't loaded here.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

nodejs/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "t42-sso-manager",
-  "version": "1.5.0",
+  "version": "1.5.1",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "t42-sso-manager",
-      "version": "1.5.0",
+      "version": "1.5.1",
       "license": "MIT",
       "dependencies": {
         "@fortawesome/fontawesome-free": "^7.3.0",
@@ -14,6 +14,7 @@
         "@simpleworkjs/app-stack": "^1.0.0",
         "@simpleworkjs/conf": "^1.2.0",
         "@simpleworkjs/directory-schema": "^1.0.0",
+        "@simpleworkjs/frontend": "^0.2.5",
         "@simpleworkjs/ldap": "^1.0.0",
         "@simpleworkjs/orm": "^0.2.8",
         "bcrypt": "^6.0.0",
@@ -1278,6 +1279,15 @@
         "node": ">=18.0.0"
       }
     },
+    "node_modules/@simpleworkjs/frontend": {
+      "version": "0.2.5",
+      "resolved": "https://registry.npmjs.org/@simpleworkjs/frontend/-/frontend-0.2.5.tgz",
+      "integrity": "sha512-PxR7UVPv3gRpdF0WsuAZplF1vYvKsEJQevVPhz9d72U+69vP/OH3tlaAXjtO/apMHfhT1viOPw2gMVOrPSxYZw==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    },
     "node_modules/@simpleworkjs/ldap": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/@simpleworkjs/ldap/-/ldap-1.0.0.tgz",