Add login functionality with password protection and create login page

templates/login.html

@@ -0,0 +1,43 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>TeslaCam Player — Login</title>
+    <link
+      rel="stylesheet"
+      href="{{ url_for('static', filename='css/style.css') }}"
+    />
+  </head>
+  <body class="login-page">
+    <div class="login-card">
+      <div class="login-brand">
+        <span class="logo" aria-hidden="true">
+          <svg viewBox="0 0 24 24">
+            <path
+              d="M12 3C7 3 3.2 4.4 3.2 4.4l.9 1.7s3.1-1 5-.9l.7 1.3C7.9 7.7 6 9 6 9s.6 2.4 3 4.6c2.5-2.2 3-4.6 3-4.6s-1.9-1.3-3.7-1.5l.6-1.3c1.9-.1 5 .9 5 .9l.9-1.7S17 3 12 3z"
+            />
+          </svg>
+        </span>
+        <h1>TeslaCam Player</h1>
+      </div>
+
+      <form method="POST" action="{{ url_for('login') }}" class="login-form">
+        <label for="password">Password</label>
+        <input
+          type="password"
+          id="password"
+          name="password"
+          placeholder="Enter password"
+          autocomplete="current-password"
+          autofocus
+          required
+        />
+        {% if error %}
+        <p class="login-error">{{ error }}</p>
+        {% endif %}
+        <button type="submit">Sign In</button>
+      </form>
+    </div>
+  </body>
+</html>