Fix account-editing bugs from real-world feedback, add editable group membership

- Edit form's Mobile Phone field was effectively required (stray validate
  attribute) -- removed.
- Service account profiles always showed the literal filler name "Service
  Account" -- hidden now, since it's not meaningful. Required computing
  isServiceAccount in User.get(), not just listDetail().
- Fresh service accounts could look uncategorized (missing from the
  Service Accounts tab, wrong isServiceAccount) for up to 5 minutes after
  creation, due to a cache-staleness race in the create route -- the user
  gets cached via User.get() before the route marks it as a service
  account. Cleared and re-fetched after marking.
- memberOf came back as a bare string instead of a one-element array for
  users in exactly one group, causing client-side permission checks to
  iterate character-by-character and incorrectly deny access -- normalized
  alongside the existing manager normalization.
- Added editable group membership on the profile page ("My groups"),
  admin-only, using the existing per-group member endpoints.

Bumps to v1.1.8.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KDEx8ghuZR61pqPXc6da9C

nodejs/package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "t42-sso-manager",
-  "version": "1.1.7",
+  "version": "1.1.8",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "t42-sso-manager",
-      "version": "1.1.7",
+      "version": "1.1.8",
       "license": "MIT",
       "dependencies": {
         "@fortawesome/fontawesome-free": "^7.3.0",