feat(workflows): add BuildAtom workflow with caching support

Introduced a new `BuildAtom` job in the GitHub Actions workflow (`Build.yml`) to handle the `.atom` build process. Implemented custom caching logic using `actions/cache` for build artifacts to improve efficiency. Added `CleanAtomDirectory` and updated `Build.cs` to support cleanup and caching configurations.

Author: DecSmith42

.github/workflows/Build.yml

@@ -50,6 +50,44 @@ jobs:
         env:
           pull-request-number: ${{ github.event.number }}
 
+  BuildAtom:
+    runs-on: ubuntu-latest
+    steps:
+      
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+      
+      - uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: '10.0.x'
+      
+      - name: cache-restore-atom-build
+        id: cache-restore-atom-build
+        uses: actions/cache/restore@v4
+        with:
+          path: |
+            '.atom'
+          key: ${{ format('{0}-atom-build-{1}', runner.os, hashFiles('_atom/**')) }}
+      
+      - name: BuildAtom
+        id: BuildAtom
+        run: ${{ steps.cache-restore-atom-build.outputs.cache-hit && format('.atom/{0} -- BuildAtom --skip --headless', runner.os == 'windows' && '_atom.exe' || '_atom') || 'dotnet run --project _atom/_atom.csproj -- BuildAtom --skip --headless' }}
+      
+      - run: rm -rf '_atom/bin'
+      
+      - run: rm -rf '_atom/obj'
+      
+      - name: cache-save-atom-build
+        id: cache-save-atom-build
+        uses: actions/cache/save@v4
+        if: steps.cache-restore-atom-build.outputs.cache-hit != true
+        with:
+          path: |
+            '.atom'
+          key: ${{ format('{0}-atom-build-{1}', runner.os, hashFiles('_atom/**')) }}
+  
   PackProjects:
     runs-on: ubuntu-latest
     steps:

_atom/Build.cs

@@ -128,6 +128,11 @@ internal partial class Build : BuildDefinition,
                         })
                         .WithOptions(WorkflowOptions.Inject.Param(WorkflowParams.PullRequestNumber,
                             "github.event.number")),
+                    WorkflowTargets.BuildAtom.WithOptions(new CleanAtomDirectory("_atom/bin"),
+                        new CleanAtomDirectory("_atom/obj"),
+                        WorkflowOptions.Cache.Save("atom-build",
+                            "${{ format('{0}-atom-build-{1}', runner.os, hashFiles('_atom/**')) }}",
+                            [WorkflowExpressions.From(".atom")])),
                     WorkflowTargets.PackProjects,
                     WorkflowTargets.PackTool.WithGithubRunsOnMatrix(PlatformNames),
                     WorkflowTargets