feat: implement user authentication features (registration, activation, and password reset)

- Added email templates for activation and password reset (`activation_email.html`, `password_reset_email.html`, etc.)
- Created forms for registration (`RegisterForm`) and login (`LoginForm`) with custom validation
- Developed new pages for account activation (`activation_success.html`, `activation_invalid.html`), password reset workflow, and profile
- Configured email backend and environment file handling in settings
- Updated header template to conditionally display profile or login links based on authentication status
- Enhanced CSS styles for authentication-related pages and forms

templates/users/password_reset_confirm.html

@@ -0,0 +1,78 @@
+{% extends '_layouts/base.html' %}
+{% load static %}
+
+{% block title %}Новый пароль{% endblock %}
+
+{% block add_css %}
+    <link rel="stylesheet" href="{% static 'css/login.css' %}">
+{% endblock %}
+
+{% block content %}
+    <div class="auth-page">
+        {% include "_fragments/header.html" %}
+        <main class="auth-section">
+            <div class="container auth-layout">
+                <section class="auth-intro auth-intro--reset">
+                    <p class="auth-kicker">Обновление пароля</p>
+                    <h1 class="auth-title">Придумайте новый пароль</h1>
+                    <p class="auth-description">
+                        Используйте надёжный пароль, который вы ещё не применяли для этого аккаунта.
+                    </p>
+                </section>
+                <section class="auth-panel">
+                    {% if validlink %}
+                        <form class="auth-form" method="post">
+                            {% csrf_token %}
+                            {% if form.non_field_errors %}
+                                <div class="auth-alert auth-alert--error">
+                                    {% for error in form.non_field_errors %}
+                                        <p>{{ error }}</p>
+                                    {% endfor %}
+                                </div>
+                            {% endif %}
+
+                            <div class="auth-field">
+                                <label for="{{ form.new_password1.id_for_label }}">Новый пароль</label>
+                                <input
+                                    id="{{ form.new_password1.id_for_label }}"
+                                    name="{{ form.new_password1.html_name }}"
+                                    type="password"
+                                    placeholder="Введите новый пароль"
+                                    autocomplete="new-password"
+                                >
+                                {% for error in form.new_password1.errors %}
+                                    <p class="auth-field-error">{{ error }}</p>
+                                {% endfor %}
+                            </div>
+
+                            <div class="auth-field">
+                                <label for="{{ form.new_password2.id_for_label }}">Подтверждение пароля</label>
+                                <input
+                                    id="{{ form.new_password2.id_for_label }}"
+                                    name="{{ form.new_password2.html_name }}"
+                                    type="password"
+                                    placeholder="Повторите пароль"
+                                    autocomplete="new-password"
+                                >
+                                {% for error in form.new_password2.errors %}
+                                    <p class="auth-field-error">{{ error }}</p>
+                                {% endfor %}
+                            </div>
+
+                            <div class="auth-actions">
+                                <button class="auth-submit" type="submit">Сохранить пароль</button>
+                            </div>
+                        </form>
+                    {% else %}
+                        <div class="auth-copy-block">
+                            <h2 class="auth-panel-title">Ссылка недействительна</h2>
+                            <p class="auth-panel-text">Возможно, ссылка уже использована или срок её действия истёк. Запросите сброс пароля повторно.</p>
+                            <a class="auth-secondary-link" href="{% url 'users:password_reset' %}">Запросить новое письмо</a>
+                        </div>
+                    {% endif %}
+                </section>
+            </div>
+        </main>
+        {% include "_fragments/footer.html" %}
+    </div>
+{% endblock %}