fix: Change Dockerfile to run ASP.NET Core instead of static nginx

The Blazor Web App requires the ASP.NET runtime to function properly,
as it uses interactive server components. Changed from nginx serving
static files to running the full .NET application.

Changes:
- Updated Dockerfile to use aspnet:9.0 runtime image
- Removed nginx configuration (no longer needed)
- Disabled HTTPS redirection (running behind reverse proxy)
- Added publish/ folder to .gitignore

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

BlazorApp/Program.cs

@@ -16,8 +16,7 @@ if (!app.Environment.IsDevelopment())
     app.UseHsts();
 }
 
-app.UseHttpsRedirection();
-
+// app.UseHttpsRedirection(); // Disabled - running behind reverse proxy
 
 app.UseAntiforgery();