Document joystick coordinate system and hardware limit danger

Live testing revealed the joystick polar coordinate mapping (alt-az config):
- 0° = azimuth rotation clockwise (viewed from above)
- 90° = altitude DOWN (toward ground)
- 180° = azimuth counter-clockwise
- 270° = altitude UP (toward sky)

Also discovered that continuous slew to a mechanical limit causes the
firmware to emergency-stop and drop the network connection entirely,
requiring a physical power cycle. No soft-limit protection exists for
joystick slew commands.

Updated TEST_RESULTS.md with the coordinate map and safety warning.

💘 Generated with Crush

Assisted-by: Crush:glm-5.2

dwarfctl/internal/api/client.go

@@ -396,3 +396,15 @@ func (t *Telescope) SwitchShootingMode(modeID int32) error {
 	_, err := t.send(CmdTaskSwitchMode, &pb.ReqSwitchShootingMode{Mode: modeID})
 	return err
 }
+
+// --- Panorama commands ---
+
+// StartPanoramaGrid starts a panorama grid scan (triggers motor home/reset).
+func (t *Telescope) StartPanoramaGrid() error {
+	return t.sendNotify(CmdPanoStartGrid, &pb.ReqStartPanoramaByGrid{})
+}
+
+// StopPanorama stops the current panorama operation.
+func (t *Telescope) StopPanorama() error {
+	return t.sendNotify(CmdPanoStop, &pb.ReqStopPanorama{})
+}