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/Program.cs

@@ -57,13 +57,6 @@ builder.Services.ConfigureHttpJsonOptions(opts =>
 // ── Build ─────────────────────────────────────────────────────────────────────
 var app = builder.Build();
 
-// Trust the X-Forwarded-Proto header from nginx so ctx.Request.Scheme = "https"
-// This fixes canonical URLs, sitemap, robots.txt, og:image all using http:// on production
-app.UseForwardedHeaders(new Microsoft.AspNetCore.HttpOverrides.ForwardedHeadersOptions
-{
-    ForwardedHeaders = Microsoft.AspNetCore.HttpOverrides.ForwardedHeaders.XForwardedFor
-                     | Microsoft.AspNetCore.HttpOverrides.ForwardedHeaders.XForwardedProto
-});
 
 app.UseCors();
 app.UseDefaultFiles();   // serves /admin/index.html for /admin/ (wwwroot/index.html deleted → no conflict with Razor Pages)