fix: improve endgame clock and gameplay stability

internal/sdkserver/api_game_clock_test.go

@@ -0,0 +1,46 @@
+package sdkserver
+
+import (
+	"encoding/json"
+	"net/http/httptest"
+	"path/filepath"
+	"testing"
+
+	"gac-hkrpg-go/internal/common"
+)
+
+func TestFakeTimeWindowCommand(t *testing.T) {
+	chdirRepoRootSDK(t)
+	t.Setenv("GAC_CONFIG", "server.json")
+	t.Setenv("GAC_GAME_CLOCK_STATE_FILE", filepath.Join(t.TempDir(), "clock.json"))
+	call := func(command string) map[string]any {
+		t.Helper()
+		w := httptest.NewRecorder()
+		apiFakeTimeCommand(w, command)
+		var response map[string]any
+		if err := json.Unmarshal(w.Body.Bytes(), &response); err != nil {
+			t.Fatal(err)
+		}
+		return response
+	}
+	if result := call("/faketime window 1000 2000"); result["success"] != true || result["unix_seconds"] != float64(1500) {
+		t.Fatalf("window command: %v", result)
+	}
+	before, err := common.ReadGameClock()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result := call("/faketime window 2000 1000"); result["success"] != false {
+		t.Fatalf("invalid window accepted: %v", result)
+	}
+	after, err := common.ReadGameClock()
+	if err != nil || before != after {
+		t.Fatalf("invalid window changed clock: %+v %v", after, err)
+	}
+	if result := call("/faketime off"); result["success"] != true {
+		t.Fatalf("reset: %v", result)
+	}
+	if state, err := common.ReadGameClock(); err != nil || state.WindowEndMS != 0 {
+		t.Fatalf("reset did not remove window: %+v %v", state, err)
+	}
+}