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>

internal/audio/audio_test.go

@@ -101,4 +101,4 @@ func TestPCMFromWAVRejectsNonCanonical(t *testing.T) {
 	if _, _, err := PCMFromWAV(wav); err == nil {
 		t.Fatalf("non-PCM format should error")
 	}
-}
+}