Fix Windows bundle build: add Bundle.proj payload step to BuildAndTest pipeline (#14650)

The Windows build in BuildAndTest.yml was missing the Bundle.proj step
that Linux/macOS have in build_sign_native.yml, producing an unbundled
CLI binary.

- Add Bundle.proj payload build step per target RID before the main build
- Default BundlePayloadPath to convention path in Common.projitems
- Fail the build with clear error if bundle payload is missing

Co-authored-by: Copilot <[email protected]>

Author: davidfowl

eng/clipack/Common.projitems

@@ -38,6 +38,17 @@
   </Target>
 
   <Target Name="_PublishProject">
+    <!--
+      Bundle payload flow:
+        1. Bundle.proj runs CreateLayout which produces a tar.gz archive (managed runtime, DCP, etc.)
+        2. Pipeline steps (BuildAndTest.yml, build_sign_native.yml, GitHub Actions) pass BundlePayloadPath to that archive
+        3. Common.projitems forwards BundlePayloadPath to the CLI publish via AdditionalProperties
+        4. Aspire.Cli.csproj embeds it as an EmbeddedResource with LogicalName="bundle.tar.gz"
+        5. BundleService.cs reads the resource at runtime via Assembly.GetManifestResourceStream and extracts with TarReader
+    -->
+    <PropertyGroup>
+      <BundlePayloadPath Condition="'$(BundlePayloadPath)' == ''">$(RepoRoot)artifacts/bundle/aspire-ci-bundlepayload-$(CliRuntime).tar.gz</BundlePayloadPath>
+    </PropertyGroup>
     <ItemGroup>
       <AdditionalProperties Include="RuntimeIdentifier=$(CliRuntime)" />
       <AdditionalProperties Include="PublishDir=$(OutputPath)" />

eng/pipelines/templates/BuildAndTest.yml

@@ -41,6 +41,20 @@ parameters:
 steps:
   # Internal pipeline: Build with pack+sign
   - ${{ if ne(parameters.runAsPublic, 'true') }}:
+    # Build bundle payload (aspire-managed) for each target RID before the main build
+    - ${{ each targetRid in parameters.targetRids }}:
+      - script: ${{ parameters.dotnetScript }}
+                msbuild
+                $(Build.SourcesDirectory)/eng/Bundle.proj
+                /restore
+                /p:Configuration=${{ parameters.buildConfig }}
+                /p:TargetRid=${{ targetRid }}
+                /p:BundleVersion=ci-bundlepayload
+                /p:SkipNativeBuild=true
+                /p:ContinuousIntegrationBuild=true
+                /bl:${{ parameters.repoLogPath }}/BundlePayload-${{ targetRid }}.binlog
+        displayName: 🟣Build bundle payload (${{ targetRid }})
+
     - script: ${{ parameters.buildScript }}
               -restore -build
               -pack