[woksin]

Changed

• The runner and its source generator create their ordinal string collections with C# 15 collection-expression arguments, and the JSON report and display-name builders avoid an extra copy and repeated list inserts. Reports and display names are unchanged (Adopt remaining .NET 11 / C# 15 items and restore the net10.0 consumer proof #113)
• The packed-package consumer checks now build and run every consumer for both .NET 10 and .NET 11, so the .NET 10 package assets are verified in a real consumer again (Adopt remaining .NET 11 / C# 15 items and restore the net10.0 consumer proof #113)

[woksin]

Reviewer notes

• Local gate on SDK 11.0.100: Release build for net10.0 and net11.0 with no warnings, and every spec project in the Test step passing on both frameworks.
• The packed-consumer step (the part this change touches) was not run locally; this PR's Build run covers it for net10.0 and net11.0.
• Cross-provider review passed with no findings.