Refactor fluent download pipelines

Beam.Models/Beam.Models.csproj

@@ -11,7 +11,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="aeqw89.PersistentData" Version="1.3.3" />
+    <PackageReference Include="aeqw89.PersistentData" Version="1.4.5" />
     <PackageReference Include="EntityFramework" Version="6.5.1" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.8">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

Beam.Models/ResourceDefinition.cs

@@ -6,16 +6,9 @@ namespace Beam.Models;
 
 public class ResourceDefinition {
     public required DataKey<ResourceDefinition> Key { get; init; }
-
     public required MetaData Meta { get; init; }
-
-    /// <summary>Map of element name to extraction config. Keys must match ^[A-Za-z0-9_-]+$</summary>
     public required Table<IDataProvider> Elements { get; init; }
-
-    /// <summary>Minimum 1 item; polymorphic segments discriminated by "type".</summary>
-    public required ILinkBuilder Url { get; init; }
-
-    /// <summary>Keys must match ^[A-Za-z0-9_-]+$</summary>
+    public required UrlLocation Location { get; init; }
     public required Table<ResourceRelation> Relations { get; init; }
 
     public class MetaData {
@@ -24,4 +17,10 @@ public class ResourceDefinition {
         public string? Description { get; init; }
         public string? ProjectUrl { get; init; }
     }
+
+    public class UrlLocation {
+        public ILinkBuilder Segments { get; init; }
+        public List<ImmutableState> States { get; init; }
+        public IStateChangerFactory StateChanger { get; init; }
+    }
 }