fix(verifier): skip llm enumeration on cross-fade frames

a navhost mid-transition carries >1 route *Screen in a collapsed
coordinate space; acting on it taps garbage (soft keyboard). real runs
showed the llm acting on 44% of steps being such frames. skip them so the
llm re-observes a settled frame next step.

internal/verifier/llm.go

@@ -130,6 +130,22 @@ type ActionCandidate struct {
 	prob float64
 }
 
+// transitionalTree reports a NavHost cross-fade: more than one route *Screen
+// alive at once. Mirrors runner.isTransitionalHierarchy so the LLM rejects the
+// same frames the verifier's transitional handling does.
+func transitionalTree(tree *hierarchy.Tree) bool {
+	screens := 0
+	for _, element := range tree.Elements {
+		if strings.HasSuffix(element.ResourceID, "Screen") {
+			screens++
+			if screens > 1 {
+				return true
+			}
+		}
+	}
+	return false
+}
+
 // verbActionKind maps a picker verb to the action kind it dispatches.
 func verbActionKind(verb string) ActionKind {
 	switch verb {
@@ -172,6 +188,14 @@ func (v *Verifier) Candidates() []ActionCandidate {
 	if v.lastTree == nil {
 		return nil
 	}
+	// A cross-fade frame carries more than one route *Screen at once (a NavHost
+	// mid-transition); its layout is mid-animation, often in a collapsed
+	// coordinate space, so acting on it taps garbage (e.g. the soft keyboard).
+	// Skip it so the LLM re-observes a settled frame next step. Mirrors the
+	// runner's isTransitionalHierarchy.
+	if transitionalTree(v.lastTree) {
+		return nil
+	}
 	root := v.runtime.GlobalObject().Get("actions")
 	if root == nil || goja.IsUndefined(root) || goja.IsNull(root) {
 		return nil

internal/verifier/llm_test.go

@@ -235,6 +235,24 @@ func TestCandidatesOffRouteLeafYieldsNothing(t *testing.T) {
 	}
 }
 
+func TestCandidatesSkipsCrossFadeFrames(t *testing.T) {
+	// Two route *Screen tags alive at once is a NavHost cross-fade: its layout is
+	// mid-animation (collapsed coordinate space), so the LLM must NOT act on it.
+	crossFade := `{
+      "attributes": {"bounds": "[0,0,320,640]"},
+      "children": [
+        {"attributes": {"resource-id": "LedgerScreen", "bounds": "[0,0,320,640]"}, "children": [
+          {"attributes": {"resource-id": "TxnSubmit", "text": "Add credit", "bounds": "[20,332,300,380]"}, "clickable": true, "enabled": true, "children": []}
+        ]},
+        {"attributes": {"resource-id": "AddTransactionScreen", "bounds": "[0,0,320,640]"}, "children": []}
+      ]
+    }`
+	v := enumVerifier(t, "{kind:'builtin', verb:'taps'}", crossFade)
+	if got := v.Candidates(); got != nil {
+		t.Errorf("cross-fade frame should yield no candidates, got %v", descriptions(got))
+	}
+}
+
 func TestCandidatesNilWithoutTreeOrActions(t *testing.T) {
 	withActions := newLoadedVerifier(t, "globalThis.actions = {kind:'builtin', verb:'taps'};")
 	if got := withActions.Candidates(); got != nil {