Add cold motion-only variant (no heaters, no extrude)

CR-X_selftest_cold_motion_only.gcode

@@ -0,0 +1,50 @@
+; ============================================================
+;  CREALITY CR-X  -  COLD MOTION-ONLY SELF-TEST
+;  NO heating, NO extrusion. Safest first pass to verify motion.
+;  Run this FIRST; if motion is clean, run the full self-test.
+; ============================================================
+M117 COLD test: init
+G90
+M107
+G28                 ; home
+G4 S2
+G1 Z20 F600
+
+; X sweep
+M117 X sweep
+G1 X5 F3000
+G1 X295 F3000
+G1 X150 F3000
+G4 S1
+; Y sweep
+M117 Y sweep
+G1 Y5 F3000
+G1 Y295 F3000
+G1 Y150 F3000
+G4 S1
+; Z sweep (watch both lead screws stay synced)
+M117 Z sweep
+G1 Z5 F600
+G1 Z380 F600
+G1 Z20 F600
+G4 S1
+; Diagonals + corners
+M117 corners
+G1 X5 Y5 F4000
+G1 X295 Y295 F4000
+G1 X5 Y295 F4000
+G1 X295 Y5 F4000
+G1 X150 Y150 F4000
+G4 S1
+; Speed range
+M117 speed check
+G1 X50 Y50 F6000
+G1 X250 Y250 F6000
+G1 X50 Y50 F1200
+G1 X150 Y150 F3000
+
+M117 parking
+G1 Z50 F600
+G1 X10 Y295 F4000
+M84
+M117 COLD test DONE