feat: Implement Sign Request Manager component for handling sign requests in the popup (WIP)

- Added SignRequestManager.js to manage sign requests, including UI states for keyspace lock, mismatch, and approval.
- Implemented methods for loading state, rendering UI, and handling user interactions (approve/reject requests).
- Integrated background message listeners for keyspace unlock events and request updates.

crypto_vault_extension/popup.html

@@ -27,6 +27,10 @@
                 <span>seconds</span>
               </div>
             </div>
+            <div class="settings-item">
+              <label for="sigSocketUrlInput">SigSocket Server</label>
+              <input type="text" id="sigSocketUrlInput" placeholder="ws://localhost:8080/ws" value="ws://localhost:8080/ws">
+            </div>
           </div>
         </div>
         <button id="themeToggle" class="btn-icon-only" title="Switch to dark mode">
@@ -189,6 +193,11 @@
           </div>
         </div>
       </div>
+
+      <!-- Sign Request Manager -->
+      <div id="signRequestContainer">
+        <!-- Sign request manager will be rendered here -->
+      </div>
     </section>
 
 
@@ -198,6 +207,7 @@
 
   <!-- Enhanced JavaScript modules -->
   <script src="js/errorHandler.js"></script>
+  <script src="popup/components/SignRequestManager.js"></script>
   <script src="popup.js"></script>
 </body>
 </html>