fix: reword 'Master Password' to 'Keyset Access Key'

Author: edeckers

src/index.html

@@ -254,7 +254,7 @@ <h3 class="text-lg font-semibold text-gray-900 mb-4">Cryptographic Key Hierarchy
                     </div>
                     <div class="flex justify-center">
                         <div class="bg-purple-100 rounded-lg p-4 shadow border-2 border-purple-300 min-w-[200px] text-center">
-                            <div class="text-sm font-medium text-purple-800">Master Password (mp)</div>
+                            <div class="text-sm font-medium text-purple-800">Keyset Access Key</div>
                             <div class="text-xs text-purple-600 mt-1">Randomly generated 256-bit symmetric key</div>
                             <div class="text-xs text-purple-600 mt-1">for encrypting asymmetric Master keys</div>
                             <div class="text-xs font-mono bg-white p-2 rounded mt-2" id="mpPreview">...</div>