feat: implement password setup link for tenant registration

When admin approves tenant registration:
- Owner account created in tenant schema (in addition to admin@localhost)
- Owner assigned 'owner' role with full permissions
- Password setup email sent with secure 7-day token link
- Owner sets password via link and auto-logs into their shop

Key changes:
- Added password_setup_token fields to TenantRegistration model
- Created tenants/services.py with formatted email service
- Modified _approve_registration to create owner account
- Added password_setup_confirm view with token validation
- Created password setup template and URL route
- Added admin action to resend password setup emails

Security:
- Token expires after 7 days
- Password not transmitted in email (secure setup link)
- Owner account inactive until password set
- Admin@localhost preserved for system administrator access

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

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

myproject/accounts/templates/accounts/password_setup_confirm.html

@@ -0,0 +1,56 @@
+{% extends 'base.html' %}
+
+{% block title %}Установка пароля{% endblock %}
+
+{% block content %}
+<div class="container">
+    <div class="form-container">
+        <h2 class="text-center mb-4">Установка пароля</h2>
+
+        <!-- Приветственное сообщение -->
+        <div class="alert alert-info">
+            <strong>Добро пожаловать!</strong> Ваш магазин <strong>{{ tenant.name }}</strong> активирован.
+            <br>Установите пароль для входа в систему.
+        </div>
+
+        <div class="tab-content">
+            <div class="tab-pane fade show active" id="setup-password">
+                <form method="post">
+                    {% csrf_token %}
+                    {% include 'accounts/password_input.html' with field_name='password1' field_label='Пароль' required=True %}
+                    {% include 'accounts/password_input.html' with field_name='password2' field_label='Подтверждение пароля' required=True %}
+                    <button type="submit" class="btn btn-primary w-100">Установить пароль и войти</button>
+                </form>
+
+                <!-- Информация -->
+                <div class="text-center mt-3">
+                    <small class="text-muted">
+                        После установки пароля вы автоматически войдете в свой магазин.
+                    </small>
+                </div>
+            </div>
+        </div>
+    </div>
+</div>
+
+<script>
+// Добавляем обработчик для показа/скрытия пароля
+document.querySelectorAll('.show-password-btn').forEach(button => {
+    button.addEventListener('click', function() {
+        const targetId = this.getAttribute('data-target');
+        const targetInput = document.getElementById(targetId);
+        const icon = this.querySelector('i');
+
+        if (targetInput.type === 'password') {
+            targetInput.type = 'text';
+            icon.classList.remove('bi-eye');
+            icon.classList.add('bi-eye-slash');
+        } else {
+            targetInput.type = 'password';
+            icon.classList.remove('bi-eye-slash');
+            icon.classList.add('bi-eye');
+        }
+    });
+});
+</script>
+{% endblock %}