Remove minimum length restriction on access codes

Any non-empty access code can now be used when adding an access
code, not just ones 8+ characters long.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

upload.php

@@ -211,8 +211,8 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
         $pw2   = $_POST['code_pw2'] ?? '';
         if ($label === '') {
             $accessMsg = 'Label is required.'; $accessType = 'error';
-        } elseif (strlen($pw) < 8) {
-            $accessMsg = 'Access code must be at least 8 characters.'; $accessType = 'error';
+        } elseif ($pw === '') {
+            $accessMsg = 'Access code is required.'; $accessType = 'error';
         } elseif ($pw !== $pw2) {
             $accessMsg = 'Access codes do not match.'; $accessType = 'error';
         } else {
@@ -373,7 +373,7 @@ input[type=file]:hover{border-color:#94a3b8}
         </div>
         <div>
           <label style="font-size:11px;font-weight:600;color:#64748b;display:block;margin-bottom:4px">Access Code</label>
-          <input type="password" name="code_pw" placeholder="min 8 characters"
+          <input type="password" name="code_pw" placeholder="access code"
                  style="width:100%;padding:7px 10px;border:1px solid #cbd5e1;border-radius:5px;font-size:13px">
         </div>
       </div>