refactor: modularize Beam into new projects and interfaces

- Introduced modularity by splitting Beam into new projects: Beam.Abstractions, Beam.Models, and Beam.Downloaders.
- Refactored existing classes into appropriate namespaces and projects.
- Replaced specific implementations with abstractions (e.g., SourceLinkBuilder to LinkBuilder, State to IState, etc.).
- Updated interfaces: added ITemplate, IArticleData, IDownloadReport, and others for improved extensibility.
- Removed deprecated classes like SourceLinkBuilder and StateChangerFactory.
- Enhanced link handling in downloaders by refactoring to use `string` over `SourceLink`.
- Consolidated shared logic under Beam.Abstractions.

Beam.Fluent/Beam.Fluent.csproj

@@ -7,16 +7,19 @@
     </PropertyGroup>
     <ItemGroup>
         <PackageReference Include="aeqw89.DataKeys" Version="2.0.1" />
-        <PackageReference Include="aeqw89.PersistentData" Version="1.1.0" />
+        <PackageReference Include="aeqw89.PersistentData" Version="1.3.3" />
         <PackageReference Include="Microsoft.Extensions.Logging" Version="9.0.7" />
         <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="9.0.7" />
         <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.7" />
         <PackageReference Include="System.Linq.Async" Version="6.0.1" />
     </ItemGroup>
     <ItemGroup>
+        <ProjectReference Include="..\Beam.Data\Beam.Data.csproj" />
+        <ProjectReference Include="..\Beam.Downloaders\Beam.Downloaders.csproj" />
         <ProjectReference Include="..\Beam.Dynamic\Beam.Dynamic.csproj">
             <PrivateAssets>all</PrivateAssets>
         </ProjectReference>
+        <ProjectReference Include="..\Beam.Exceptions\Beam.Exceptions.csproj" />
         <ProjectReference Include="..\Beam.Models\Beam.Models.csproj" />
         <ProjectReference Include="..\Beam.Playwright\Beam.Playwright.csproj">
             <PrivateAssets>all</PrivateAssets>
@@ -24,8 +27,6 @@
         <ProjectReference Include="..\Beam.Stealth\Beam.Stealth.csproj">
             <PrivateAssets>all</PrivateAssets>
         </ProjectReference>
-        <ProjectReference Include="..\Beam\Beam.csproj">
-            <PrivateAssets>all</PrivateAssets>
-        </ProjectReference>
+        <ProjectReference Include="..\Beam\Beam.csproj" />
     </ItemGroup>
 </Project>

Beam.Fluent/DownloadBuilder.ContextStage.cs

@@ -1,6 +1,10 @@
-using HtmlAgilityPack;
+using Beam.Abstractions;
+using Beam.Models;
+using HtmlAgilityPack;
 using Beam.Playwright;
 using Beam.Stealth;
+using Beam;
+using Beam.Downloaders;
 
 namespace Beam.Fluent {
 public static partial class DownloadBuilder<RawType, OutType> {
@@ -33,7 +37,7 @@ public static partial class DownloadBuilder<RawType, OutType> {
                 return this;
             }
 
-            public IContextStage WithRetryReporter(IProgress<RetryReport> reporter) {
+            public IContextStage WithRetryReporter(IProgress<IRetryReport> reporter) {
                 _ctxBuilder.WithRetryReporter(reporter);
                 return this;
             }
@@ -163,7 +167,7 @@ public static partial class DownloadBuilder<RawType, OutType> {
             }
 
             private IAsyncEnumerator<Ordered<OutType>> ConstructDownloader(DownloadContext<RawType> context) {
-                var copyOfContext = context.CreateBuilder().Build();
+                var copyOfContext = DownloadContextBuilder<RawType>.FromContext(context).Build();
                 return _useFragments switch {
                     true => new SequentialFragmentDownloader<RawType, OutType>(
                         copyOfContext,

Beam.Fluent/DownloadBuilder.DownloadStage.cs

@@ -1,5 +1,6 @@
 using System.Collections.Concurrent;
 using System.Text.Json;
+using Beam.Models;
 
 namespace Beam.Fluent {
 public static partial class DownloadBuilder<RawType, OutType> {

Beam.Fluent/DownloadBuilder.IAlternativeLinkStage.cs

@@ -1,7 +1,9 @@
-namespace Beam.Fluent {
+using Beam.Models;
+
+namespace Beam.Fluent {
 public static partial class DownloadBuilder<RawType, OutType> {
         public interface IAlternativeLinkStage {
-            IAlternativeTransformStage WithLinks(IEnumerable<SourceLink> links);
+            IAlternativeTransformStage WithLinks(IEnumerable<string> links);
         }
     }
 }

Beam.Fluent/DownloadBuilder.IAlternativeTransformStage.cs

@@ -1,4 +1,6 @@
-namespace Beam.Fluent {
+using Beam.Models;
+
+namespace Beam.Fluent {
 public static partial class DownloadBuilder<RawType, OutType> {
         public interface IAlternativeTransformStage {
             IContextStage WithTransformer(AsyncTransformer<RawType, OutType> transformer);

Beam.Fluent/DownloadBuilder.IContextStage.cs

@@ -1,4 +1,7 @@
-using Beam.Playwright;
+using Beam.Abstractions;
+using Beam.Downloaders;
+using Beam.Models;
+using Beam.Playwright;
 using Beam.Stealth;
 
 namespace Beam.Fluent {
@@ -7,7 +10,7 @@ public static partial class DownloadBuilder<RawType, OutType> {
             IContextStage Configure(Action<DownloadContextBuilder<RawType>> configure);
             IContextStage WithParallelism(int degree);
             IContextStage WithTimeout(TimeSpan timeout);
-            IContextStage WithRetryReporter(IProgress<RetryReport> reporter);
+            IContextStage WithRetryReporter(IProgress<IRetryReport> reporter);
             DownloadEnumerable<OutType> Build();
             IContextStage UseFragments();
             IContextStage UsePlaywright(PlaywrightAsyncManipulator manipulator);

Beam.Fluent/DownloadBuilder.ITransformStage.cs

@@ -1,4 +1,5 @@
 using Beam.Dynamic;
+using Beam.Models;
 
 namespace Beam.Fluent {
 public static partial class DownloadBuilder<RawType, OutType> {

Beam.Fluent/DownloadBuilder.LinkStage.cs

@@ -1,10 +1,11 @@
-using Beam.Models;
+using Beam.Data;
+using Beam.Downloaders;
+using Beam.Dynamic;
+using Beam.Models;
 
 namespace Beam.Fluent {
     public static partial class DownloadBuilder<RawType, OutType> {
         /* ──────────────────────────── Stage types ─────────────────────────── */
-
-
         private sealed record LinkStage(
             WebResource Source,
             State Initial,
@@ -22,7 +23,7 @@ namespace Beam.Fluent {
 
             public ITransformStage WithLinkGenerator() {
                 var template = Data.Templates[Source.Key];
-                var generator = SourceLinkEnumerable.FromGenerator(new OrderedSourceLinkGenerator(
+                var generator = StringEnumerable.FromGenerator(new OrderedLinkGenerator(
                     template.Builder,
                     new NumberedStateChanger(template.Factory.Behavior),
                     Initial, endState));
@@ -31,7 +32,7 @@ namespace Beam.Fluent {
                 return new TransformStage(Source, Data, CtxBuilder);
             }
 
-            public IAlternativeTransformStage WithLinks(IEnumerable<SourceLink> links) {
+            public IAlternativeTransformStage WithLinks(IEnumerable<string> links) {
                 CtxBuilder.WithLinks(links);
                 return new TransformStage(Source, Data, CtxBuilder);
             }

Beam.Fluent/DownloadBuilder.TransformStage.cs

@@ -1,4 +1,6 @@
-using Beam.Dynamic;
+using Beam.Data;
+using Beam.Downloaders;
+using Beam.Dynamic;
 using Beam.Models;
 
 namespace Beam.Fluent {

Beam.Fluent/DownloadBuilder.cs

@@ -3,6 +3,8 @@ using Beam;
 using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;
+using Beam.Data;
+using Beam.Downloaders;
 using Beam.Models;
 
 namespace Beam.Fluent {
@@ -22,7 +24,7 @@ namespace Beam.Fluent {
 
         private static ILinkStage Create(DataKey<ResourceDictionary> resourceDict, BeamDataContext data, string kind) {
             var (source, initial) = Resolve(resourceDict, kind, data);
-            var ctxBuilder = new DownloadContextBuilder<RawType>().WithLinks(Array.Empty<SourceLink>()); // placeholder, filled later.
+            var ctxBuilder = new DownloadContextBuilder<RawType>().WithLinks([]); // placeholder, filled later.
             return new LinkStage(source, initial, data, ctxBuilder);
         }