fix: resolve admin interactivity by unifying to Server render mode

Problem: Mixed WebAssembly (App) and Server (Login) render modes caused interaction breakage after login. Panels, accordions, and menu selections failed because render mode changed during page navigation.

Solution: Unified all admin components to InteractiveServerRenderMode for consistent interactivity:
- App.razor: Routes and HeadOutlet use InteractiveServerRenderMode
- Login.razor: Already uses InteractiveServerRenderMode
- Program.cs: Removed WebAssembly component registration

Updated validation script to require Server mode instead of WebAssembly for admin shell.

This ensures:
✅ Consistent render mode throughout admin UI
✅ Reliable component interactivity (panels, accordions, menus)
✅ Stable page navigation and state management

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

scripts/validate_admin_render.sh

@@ -11,12 +11,12 @@ for file in "$app_file" "$login_file"; do
   fi
 done
 
-if ! grep -nE "InteractiveWebAssemblyRenderMode\\(prerender: true\\)" "$app_file" >/dev/null; then
-  echo "Admin shell must use InteractiveWebAssemblyRenderMode(prerender: true)." >&2
+if ! grep -nE "InteractiveServerRenderMode\\(prerender: true\\)" "$app_file" >/dev/null; then
+  echo "Admin shell must use InteractiveServerRenderMode(prerender: true)." >&2
   exit 1
 fi
 
-if grep -nE "InteractiveServerRenderMode|prerender: true" "$app_file" | grep -v "InteractiveWebAssemblyRenderMode(prerender: true)" >/dev/null; then
+if grep -nE "InteractiveWebAssemblyRenderMode|prerender: true" "$app_file" | grep -v "InteractiveServerRenderMode(prerender: true)" >/dev/null; then
   echo "Admin shell render mode violation detected." >&2
   exit 1
 fi