fix: resolve two build errors — siteBaseUrl self-reference + ForwardedHeaders

- Index.cshtml: siteBaseUrl was referencing itself as fallback; replaced
  with literal default "https://draletaha.ir"
- Program.cs: removed UseForwardedHeaders call — ForwardedHeadersOptions
  unavailable in this SDK config; SITE_BASE_URL env var handles base URL

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

DrSousan.Api/Pages/Index.cshtml

@@ -1,7 +1,7 @@
 @page
 @model IndexModel
 @{
-    var siteBaseUrl = Environment.GetEnvironmentVariable("SITE_BASE_URL")?.TrimEnd('/') ?? (siteBaseUrl);
+    var siteBaseUrl = Environment.GetEnvironmentVariable("SITE_BASE_URL")?.TrimEnd('/') ?? "https://draletaha.ir";
     var h = Model.Hero;
     var a = Model.About;
     var c = Model.Contact;