KY UFO toys (rtsp://…:7070/webcam): turn the picture 90° counter-clockwise #200

The K200 (Wi‑Fi FLY-UFO-…, KY UFO family, #187/#196) plays over rtsp://192.168.1.1:7070/webcam, but its camera is mounted sideways. The picture comes rotated (a mug lies on its side, handle up), as a portrait strip in the middle of a landscape screen. Turned 90° counter-clockwise it is upright and fills the screen (tester's request in #196).

Plan: in the toy's own path, not as a general camera setting (that one is #201):

• For rtsp://<host>:7070/webcam (the same detection that turns on the 7099 heartbeat), draw the MJPEG frames turned 90° CCW and fit the turned frame (landscape) to the screen.
• URL option to override: ?rotate=0|90|180|270 (degrees counter-clockwise), with ?rotate=0 to switch it off if a unit is mounted differently.
• Shown in /stats.json; the debug snapshot and the long-press screenshot are turned the same way.

Goes into the toy test build on #188.