Feat: Add group categories to all macros for Mainsail/Fluidd UI

Calibration macros (calibration/*.cfg):
- All calibration macros grouped under 'Calibration'

Printing macros (user_settings_clean.cfg):
- PRINT_START, PRINT_END → 'Printing'
- QUICK_TOUCH, CALIBRATE_PROBE → 'Calibration'
- BABYZ_PLUS, BABYZ_MINUS → 'Helpers'

This organizes macros in Mainsail/Fluidd UI instead of showing
all under 'Uncategorized'.

calibration/test_patterns.cfg

@@ -9,6 +9,7 @@
 # ----------------------------------------------------------------------------
 [gcode_macro PA_TEST_PATTERN]
 description: Print Pressure Advance test pattern
+group: Calibration
 gcode:
     {% set START_PA = params.START|default(0.01)|float %}
     {% set END_PA = params.END|default(0.05)|float %}
@@ -66,6 +67,7 @@ gcode:
 # ----------------------------------------------------------------------------
 [gcode_macro FLOW_TEST_CUBE]
 description: Print flow rate calibration cube
+group: Calibration
 gcode:
     {% set START_FLOW = params.START|default(0.90)|float %}
     {% set END_FLOW = params.END|default(1.10)|float %}
@@ -135,6 +137,7 @@ gcode:
 # ----------------------------------------------------------------------------
 [gcode_macro RETRACT_TEST_PATTERN]
 description: Print retraction test pattern
+group: Calibration
 gcode:
     {% set START_RETRACT = params.START|default(1.0)|float %}
     {% set END_RETRACT = params.END|default(4.0)|float %}
@@ -210,6 +213,7 @@ gcode:
 # ----------------------------------------------------------------------------
 [gcode_macro TEMP_TOWER]
 description: Print temperature tower
+group: Calibration
 gcode:
     {% set START_TEMP = params.START|default(195)|int %}
     {% set END_TEMP = params.END|default(225)|int %}