fix: configure Blazor WebAssembly admin UI and fix middleware pipeline

- Add index.html entry point for WASM client
- Deploy 450+ WASM assembly files to wwwroot/admin
- Remove problematic UseBlazorFrameworkFiles middleware
- Fix static file serving for framework JS/WASM resources
- Update middleware ordering for proper static file handling
- Login page now loads and serves admin dashboard

Changes verified with server logs showing successful WASM file serving
at 200 status with proper gzip compression.

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

src/TaxBaik.Web/Program.cs

@@ -366,11 +366,7 @@ catch (Exception ex)
 app.UsePathBase("/taxbaik");
 app.UseResponseCompression();
 
-// WASM 프레임워크 파일 (정적 파일 전에)
-app.UseBlazorFrameworkFiles("/admin");
-app.UseBlazorFrameworkFiles("/portal");
-
-// 정적 파일 제공 (정적 경로별)
+// 정적 파일 제공 (WASM 프레임워크 파일 포함)
 app.UseStaticFiles();
 app.UseStaticFiles("/admin");
 app.UseStaticFiles("/portal");