feat: Phase 5 — maps_navigate, and read the screen before the input

The Maps recipe: open the search box, type the place, and confirm the
result list names it. Every label comes from a live uiautomator dump
(search_omnibox_text_box, typed_suggest_container, the account sheet),
never from a guess. Text only, one step_timeout/total_timeout, guards for
the account sheet.

The first live run exposed an ordering bug in expect_change. A dump is not
instant, so a baseline taken after the input already showed the app's
response and the check could never see a wedge; it failed against a
healthy Maps. The engine now reads the screen before the step above runs
and hands that signature to the check. Each retry re-reads it.

Live: maps_navigate ok in 27.6s, result list names "Melbourne Museum".
The wedge reason and its bounded retry are demonstrated with a probe
recipe whose input changes nothing; a real wedge could not be forced, and
docs/phase-5-maps-recipe.md says so plainly.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

internal/recipe/recipe_test.go

@@ -178,6 +178,56 @@ func TestSpotifyRecipeIsValid(t *testing.T) {
 	}
 }
 
+// TestMapsRecipeIsValid keeps the shipped Phase 5 recipe honest: a typo in
+// recipes/maps_navigate.recipe fails the test suite, not the phone.
+func TestMapsRecipeIsValid(t *testing.T) {
+	rec, err := Load(filepath.Join("..", "..", "recipes", "maps_navigate.recipe"))
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if rec.Task != "maps_navigate" || rec.App != "com.google.android.apps.maps" {
+		t.Fatalf("header = %q / %q", rec.Task, rec.App)
+	}
+	if len(rec.MissingParams(map[string]string{"query": "x"})) != 0 {
+		t.Fatal("maps_navigate must accept a query parameter")
+	}
+	if len(rec.Guards) == 0 {
+		t.Fatal("maps_navigate needs guards for screens it must not tap")
+	}
+
+	var sawForeground, sawChange int
+	for i, s := range rec.Steps {
+		switch s.Verb {
+		case "foreground":
+			sawForeground++
+		case "expect_change":
+			sawChange++
+			// The engine reads the screen before the step above, so the check
+			// needs a step above it.
+			if i == 0 {
+				t.Fatal("expect_change must have a step above it")
+			}
+		}
+		// No coordinates, nowhere: every argument is text, a duration or a
+		// placeholder, never a bare screen coordinate.
+		for _, a := range s.Args {
+			if _, err := strconv.Atoi(a); err == nil {
+				t.Fatalf("step %s has a bare number %q as an argument: this recipe must name text, not coordinates", s.Verb, a)
+			}
+		}
+	}
+	if sawForeground == 0 {
+		t.Fatal("maps_navigate must pin the foreground app before matching text")
+	}
+	if sawChange == 0 {
+		t.Fatal("maps_navigate must check that its inputs changed the screen (the wedged-app check)")
+	}
+	last := rec.Steps[len(rec.Steps)-1]
+	if last.Verb != "wait" || last.Args[0] != "{query}" {
+		t.Fatalf("the last step must confirm the result list names the place, got %+v", last)
+	}
+}
+
 func TestLoadAndList(t *testing.T) {
 	dir := t.TempDir()
 	write := func(name, body string) {
@@ -290,7 +340,7 @@ func TestForegroundStep(t *testing.T) {
 func TestStepDurationsAreRecorded(t *testing.T) {
 	rec := &Recipe{StepTimeout: time.Second}
 	step := Step{Verb: "sleep", Timeout: 50 * time.Millisecond}
-	sr := executeStep(adb.New(""), rec, step, 2, nil, 0, 0, time.Now().Add(time.Minute), func(string, ...any) {})
+	sr := executeStep(adb.New(""), rec, step, 2, nil, 0, 0, time.Now().Add(time.Minute), "", func(string, ...any) {})
 	if !sr.OK {
 		t.Fatalf("sleep step failed: %s", sr.Error)
 	}