fix: stub hook send in tests for CI without /dev/tty

Avoid opening /dev/tty during unit tests so GitHub Actions can run
go test without a controlling terminal.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/hook/hook_test.go

@@ -10,6 +10,7 @@ import (
 )
 
 func TestCursorStopHookDisabled(t *testing.T) {
+	stubCursorSend(t)
 	cfg := config.Default()
 	cfg.Events.Stop = false
 	err := RunCursor(bytes.NewReader([]byte(`{"workspace_roots":["/tmp/proj"]}`)), cfg, "stop", &bytes.Buffer{})