api: establish 1.x compatibility baseline

Author: mleem97

eng/PublicApi.Shipped.txt

@@ -0,0 +1,11 @@
+# gregCore public API baseline
+#
+# This file is append-only inside the 1.x release line. Public API removals,
+# namespace moves and signature changes require a 2.0 release or a legacy shim.
+# The initial detailed baseline is generated by the API compatibility job once
+# production types are moved into gregCore.Abstractions and gregCore.SDK.
+
+GregCore.Abstractions.ILoaderHost
+GregCore.Abstractions.IGregLogSink
+GregCore.Abstractions.ICompatibilityContext
+GregCore.Abstractions.LoaderRuntimeInfo