feat: add user roles management UI with owner access control

- Added role management views (list, create, edit, delete)
- Created user_roles URL routing
- Added role management templates with Bootstrap styling
- Updated navbar with Roles link for owners and superusers
- Enhanced decorators and mixins with superuser bypass
- Added assign_owner_role.py utility script

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

myproject/user_roles/templates/user_roles/user_role_edit.html

@@ -0,0 +1,63 @@
+{% extends "base.html" %}
+
+{% block title %}Изменить роль пользователя{% endblock %}
+
+{% block content %}
+<div class="container mt-4">
+    <div class="row justify-content-center">
+        <div class="col-md-6">
+            <div class="card">
+                <div class="card-header">
+                    <h4 class="mb-0">Изменить роль пользователя</h4>
+                </div>
+                <div class="card-body">
+                    {% if messages %}
+                        {% for message in messages %}
+                            <div class="alert alert-{{ message.tags }} alert-dismissible fade show" role="alert">
+                                {{ message }}
+                                <button type="button" class="btn-close" data-bs-dismiss="alert"></button>
+                            </div>
+                        {% endfor %}
+                    {% endif %}
+
+                    <div class="mb-3">
+                        <label class="form-label">Пользователь:</label>
+                        <p class="form-control-plaintext">{{ user_role.user.email }} ({{ user_role.user.name }})</p>
+                    </div>
+
+                    <form method="post">
+                        {% csrf_token %}
+
+                        <div class="mb-3">
+                            <label for="role" class="form-label">Роль *</label>
+                            <select class="form-select" id="role" name="role" required>
+                                {% for role in roles %}
+                                    <option value="{{ role.code }}" {% if role.code == user_role.role.code %}selected{% endif %}>
+                                        {{ role.name }} - {{ role.description }}
+                                    </option>
+                                {% endfor %}
+                            </select>
+                        </div>
+
+                        <div class="mb-3">
+                            <div class="form-check">
+                                <input class="form-check-input" type="checkbox" id="is_active" name="is_active"
+                                       {% if user_role.is_active %}checked{% endif %}>
+                                <label class="form-check-label" for="is_active">
+                                    Активен
+                                </label>
+                            </div>
+                            <div class="form-text">Снимите галочку, чтобы временно отключить доступ</div>
+                        </div>
+
+                        <div class="d-flex justify-content-between">
+                            <a href="{% url 'user_roles:list' %}" class="btn btn-secondary">Отмена</a>
+                            <button type="submit" class="btn btn-primary">Сохранить изменения</button>
+                        </div>
+                    </form>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+{% endblock %}