internal/app: modularise outcome finalise

This is the initial effort of splitting up host and container side of finalisation for params to shim. The new layout also enables much finer grained unit testing of each step, as well as partition access to per-app state for each step.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/app/app.go

@@ -18,8 +18,8 @@ func Main(ctx context.Context, msg container.Msg, config *hst.Config) {
 		log.Fatal(err)
 	}
 
-	seal := outcome{id: &stringPair[state.ID]{id, id.String()}, syscallDispatcher: direct{}}
-	if err := seal.finalise(ctx, msg, config); err != nil {
+	seal := outcome{syscallDispatcher: direct{}}
+	if err := seal.finalise(ctx, msg, &id, config); err != nil {
 		printMessageError("cannot seal app:", err)
 		os.Exit(1)
 	}