fix: resolve script loading timing issue with admin-session.js

Problem: App.razor's inline initialization script was executing before
admin-session.js was fully loaded, causing window.taxbaikAdminSession to be
undefined. This prevented form binding and login event handler attachment.

Flow problem:
1. admin-session.js starts loading (async)
2. inline <script> executes immediately (sync)
3. window.taxbaikAdminSession is still undefined
4. bindLoginForm() call fails silently
5. form submit handler never attached
6. login button click doesn't trigger form submission

Solution: Add retry loop with 50ms intervals until admin-session.js is loaded.
This ensures form binding happens after the module is ready.

Result: Form submission now works correctly, completing the login flow.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/TaxBaik.Web.Client/Components/Admin/App.razor

@@ -50,15 +50,24 @@
     <script src="/taxbaik/js/admin-session.js"></script>
     <script src="/taxbaik/_framework/blazor.webassembly.js"></script>
     <script>
-        if (window.taxbaikAdminSession && typeof window.taxbaikAdminSession.initErrorLogging === 'function') {
-            window.taxbaikAdminSession.initErrorLogging();
-        }
-        if (window.taxbaikAdminSession && typeof window.taxbaikAdminSession.bindLoginForm === 'function') {
-            window.taxbaikAdminSession.bindLoginForm();
-        }
-        if (window.taxbaikAdminSession && typeof window.taxbaikAdminSession.watchReconnect === 'function') {
-            window.taxbaikAdminSession.watchReconnect();
+        // admin-session.js 로드 완료 대기 후 초기화
+        function initSession() {
+            if (window.taxbaikAdminSession) {
+                if (typeof window.taxbaikAdminSession.initErrorLogging === 'function') {
+                    window.taxbaikAdminSession.initErrorLogging();
+                }
+                if (typeof window.taxbaikAdminSession.bindLoginForm === 'function') {
+                    window.taxbaikAdminSession.bindLoginForm();
+                }
+                if (typeof window.taxbaikAdminSession.watchReconnect === 'function') {
+                    window.taxbaikAdminSession.watchReconnect();
+                }
+            } else {
+                // admin-session.js가 아직 로드되지 않았으면 재시도
+                setTimeout(initSession, 50);
+            }
         }
+        initSession();
     </script>
 </body>
 </html>