fix(seo): list pub.dev packages on the pub registry page

src/backend/PkgDiff.API/Controllers/SitemapController.cs

@@ -2,7 +2,6 @@
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Caching.Memory;
 using PkgDiff.Application.Interfaces;
-using PkgDiff.Shared.Constants;
 
 namespace PkgDiff.API.Controllers;
 
@@ -25,6 +24,9 @@ public class SitemapController : ControllerBase
         "/cookies",
     };
 
+    // The values used in public URLs, where pub.dev is "pub"
+    private static readonly string[] RegistryHubs = { "nuget", "npm", "pypi", "pub", "packagist", "maven" };
+
     private readonly IAdminPackageService _adminService;
     private readonly IMemoryCache _memory;
     private readonly ILogger<SitemapController> _logger;
@@ -73,7 +75,7 @@ private async Task<string> BuildSitemapAsync()
             AppendUrl(xml, path, null);
         }
 
-        foreach (var registry in RegistryNames.All)
+        foreach (var registry in RegistryHubs)
         {
             AppendUrl(xml, $"/packages?registry={registry}", null);
         }

src/frontend/public/llms.txt

@@ -17,7 +17,7 @@ pkgdiff helps developers decide whether a dependency upgrade is safe. It combine
 - [npm packages](https://pkgdiff.dev/packages?registry=npm)
 - [PyPI packages](https://pkgdiff.dev/packages?registry=pypi)
 - [Maven packages](https://pkgdiff.dev/packages?registry=maven)
-- [pub.dev packages](https://pkgdiff.dev/packages?registry=pub.dev)
+- [pub.dev packages](https://pkgdiff.dev/packages?registry=pub)
 - [Packagist packages](https://pkgdiff.dev/packages?registry=packagist)
 
 ## Package pages

src/frontend/src/app/features/packages/packages-list.ts

@@ -15,12 +15,12 @@ const REGISTRY_LABELS: Record<string, string> = {
     npm: 'npm',
     pypi: 'PyPI',
     maven: 'Maven',
-    'pub.dev': 'pub.dev',
+    pub: 'pub.dev',
     packagist: 'Packagist',
 };
 
 const REGISTRY_ALIASES: Record<string, string> = {
-    pub: 'pub.dev',
+    'pub.dev': 'pub',
     composer: 'packagist',
 };
 
@@ -259,5 +259,9 @@ export class PackagesListComponent {
                 : 'Browse packages from NuGet, npm, PyPI, Maven, pub.dev and Packagist. See version history, breaking changes and categorized release notes.',
             url: query ? `/packages?${query}` : '/packages',
         });
+
+        if (!this.isLoading() && this.registryPackages().length === 0) {
+            this.seo.setNoIndex();
+        }
     }
 }