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/templates/profile/_text_field.html

@@ -0,0 +1,7 @@
+{% load i18n %}
+<div class="field{% if field.errors %} has-error{% endif %}">
+  <label for="{{ field.id_for_label }}">{{ label }}</label>
+  <input type="{{ input_type|default:'text' }}" name="{{ field.html_name }}" id="{{ field.id_for_label }}" value="{{ field.value|default_if_none:'' }}" autocomplete="{{ autocomplete }}" maxlength="{{ max_length }}"{% if required %} required{% endif %}{% if field.errors %} aria-invalid="true"{% endif %} aria-describedby="{{ field.id_for_label }}-hint{% if field.errors %} {{ field.id_for_label }}-error{% endif %}">
+  {% if hint %}<p class="hint" id="{{ field.id_for_label }}-hint">{{ hint }}</p>{% else %}<span id="{{ field.id_for_label }}-hint"></span>{% endif %}
+  {% if field.errors %}<div id="{{ field.id_for_label }}-error">{% for error in field.errors %}<p class="error">{{ error }}</p>{% endfor %}</div>{% endif %}
+</div>