fix(trace): an action names the generator that produced it

The setup exclusion landed for the model arm only, because only a model
pick stamped a source. A seeded run returned setup's action through the
same entry with no marker, so its denominator still counted the login
while the model arm's did not, and the two are compared.

serializeAction names setup and seeded on the wire, so both arms are
counted by one rule. An already-recorded trace names nothing and keeps
exactly the count it was reported with; unattributed_actions counts those
steps so the old denominator cannot pass as the new one. TraceVersion is
deliberately unbumped: oracle-reduction refuses a differing version, and
a bump would make all 169 recorded runs unreplayable.

internal/runner/runner.go

@@ -82,9 +82,8 @@ type Summary struct {
 	// GeneratorActions counts the dispatched actions the generator chose. The
 	// spec's setup drives the app into its starting position before the
 	// generator is consulted, so a run at zero here explored nothing however
-	// many actions its login fired. Only the model generator separates the two:
-	// the seeded picker resolves setup precedence inside the one JS call it
-	// makes, so everything it returns counts as the generator's.
+	// many actions its login fired. Both generators separate the two the same
+	// way, by the producer each action names on the trace.
 	GeneratorActions int
 }
 
@@ -506,7 +505,7 @@ func Run(ctx context.Context, options Options) (Summary, error) {
 		}
 		if nextErr == nil && !applySkipped {
 			summary.DispatchedActions++
-			if generatorChoseAction(actionSource) {
+			if generatorChoseAction(traceAction) {
 				summary.GeneratorActions++
 			}
 		}
@@ -1580,7 +1579,12 @@ func driverIsAndroid(ctx context.Context, options Options, logger *slog.Logger)
 }
 
 func traceActionFor(action verifier.Action, tree *hierarchy.Tree) *trace.Action {
-	traceAction := &trace.Action{Kind: string(action.Kind), X: action.X, Y: action.Y}
+	traceAction := &trace.Action{
+		Kind:   string(action.Kind),
+		X:      action.X,
+		Y:      action.Y,
+		Source: action.Source,
+	}
 	switch action.Kind {
 	case verifier.ActionKindTap, verifier.ActionKindDoubleTap, verifier.ActionKindLongPress:
 		traceAction.Selector = action.On