Add image upload preview functionality; update titles and templates for consistency

Co-authored-by: Copilot <copilot@github.com>

frontend/app/templates/register.html

@@ -1,14 +1,19 @@
-{% extends "base.html" %}
-{% block title %}Register — AI Allucanget{% endblock %}
-{% block content %}
+{% extends "base.html" %} {% block title %}Register — All You Can GET AI{%
+endblock %} {% block content %}
 <div class="card">
   <h1>Create account</h1>
   <form method="post">
     <label for="email">Email</label>
-    <input id="email" name="email" type="email" required autofocus>
+    <input id="email" name="email" type="email" required autofocus />
 
     <label for="password">Password</label>
-    <input id="password" name="password" type="password" required minlength="8">
+    <input
+      id="password"
+      name="password"
+      type="password"
+      required
+      minlength="8"
+    />
 
     <button type="submit">Register</button>
   </form>