feat: support setting H.264 GOP

perf: merge H.264 SPS and PPS into I-frame
perf: refactor MJPEG frame detection
perf: update log timestamp to millisecond precision
perf: update script `update-nanokvm.py`
chore: bump Go to 1.23
chore: bump golang.org/x/net to v0.37.0

server/common/screen.go

@@ -8,6 +8,7 @@ type Screen struct {
 	FPS     int
 	Quality uint16
 	BitRate uint16
+	GOP     uint8
 }
 
 var (
@@ -46,6 +47,7 @@ func GetScreen() *Screen {
 			Quality: 80,
 			FPS:     30,
 			BitRate: 3000,
+			GOP:     30,
 		}
 	})
 
@@ -70,6 +72,9 @@ func SetScreen(key string, value int) {
 
 	case "fps":
 		screen.FPS = validateFPS(value)
+
+	case "gop":
+		screen.GOP = uint8(value)
 	}
 }