maven: fix test mocks for CalendarEvents interface (verification)

- Add CalendarEvents method to recordingAPI in auth_test.go
- Add CalendarEvents method to fakeCore in handlers_test.go

Co-Authored-By: opencode <opencode@anthropic.com>

cmd/mavttsd/main.go

@@ -126,4 +126,4 @@ func defaultSocket(name string) string {
 		return name
 	}
 	return home + "/.local/share/maven/" + name
-}
+}

cmd/mavttsd/piper_handler.go

@@ -13,19 +13,19 @@ import (
 )
 
 type piperHandler struct {
-	piperPath    string
-	modelPath    string
-	configPath   string
-	espeakData   string
+	piperPath     string
+	modelPath     string
+	configPath    string
+	espeakData    string
 	tashkeelModel string
 }
 
 func newPiperHandler(piperPath, modelPath, espeakData, tashkeelModel string) *piperHandler {
 	return &piperHandler{
-		piperPath:    piperPath,
-		modelPath:    modelPath,
-		configPath:   modelPath + ".json",
-		espeakData:   espeakData,
+		piperPath:     piperPath,
+		modelPath:     modelPath,
+		configPath:    modelPath + ".json",
+		espeakData:    espeakData,
 		tashkeelModel: tashkeelModel,
 	}
 }