Add user auth, personal cabinet, admin panel and first admin bootstrap

Co-authored-by: Cursor <cursoragent@cursor.com>

app/templates/auth/login.html

@@ -0,0 +1,36 @@
+{% extends "base.html" %}
+
+{% block title %}Вход — PhotoHost{% endblock %}
+
+{% block content %}
+<section class="auth-section">
+    <div class="container auth-container">
+        <div class="auth-card">
+            <h1 class="auth-card__title">Вход</h1>
+            <p class="auth-card__subtitle">Войдите в аккаунт для загрузки фото</p>
+
+            {% include "partials/alerts.html" %}
+
+            <form method="post" class="auth-form">
+                <div class="form-group">
+                    <label for="login">Логин или email</label>
+                    <input type="text" id="login" name="login" required autocomplete="username" placeholder="username или email@example.com">
+                </div>
+                <div class="form-group">
+                    <label for="password">Пароль</label>
+                    <input type="password" id="password" name="password" required autocomplete="current-password" placeholder="••••••••">
+                </div>
+                <label class="form-checkbox">
+                    <input type="checkbox" name="remember">
+                    <span>Запомнить меня</span>
+                </label>
+                <button type="submit" class="btn btn--primary btn--full">Войти</button>
+            </form>
+
+            <p class="auth-card__footer">
+                Нет аккаунта? <a href="{{ url_for('auth.register') }}">Зарегистрироваться</a>
+            </p>
+        </div>
+    </div>
+</section>
+{% endblock %}