feat: add profile edit

Profile page at /profile with first name, last name, display name, telephone and mobile read from AD and shown with the username and e-mail. Only changed fields are written through the directory adapter in one transaction with the audit entry (field names only); numbers are accepted in any common notation and stored as +country code and digits; names are required. Plain-language errors per field, German text and tests; review findings logged in the plan.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FocPJ75XPma7TcuYEMy8zm

portal/shell/menu.py

@@ -22,7 +22,15 @@ class Group:
 
 
 MENU = (
-    Group(None, None, (Entry(_("Home"), "home"), Entry(_("Change password"), "password"))),
+    Group(
+        None,
+        None,
+        (
+            Entry(_("Home"), "home"),
+            Entry(_("Profile"), "profile"),
+            Entry(_("Change password"), "password"),
+        ),
+    ),
     Group(
         _("Publishing"),
         "publisher",