CAM: Convert tapping operation to experimental feature, Add tap pitch support, improve tapping logic, and update toolbit schema and legacy linuxcnc post

CAM/App/PathSegmentWalker.cpp
- Add G74 to drill/tap/bore G-code recognition for tapping cycles

CAM/InitGui.py
- Move CAM_Tapping command behind experimental feature flag
- Only group drilling/tapping commands if both are enabled

CAM/Path/Base/Generator/tapping.py
- Add pitch and spindle_speed parameters to tapping.generate
- Output S (spindle speed) and F (pitch) in generated G-code

CAM/Path/Op/Tapping.py
- Require Pitch property for tap tools and SpindleSpeed for tool controllers
- Pass pitch and spindle speed to tapping.generate
- Use SpindleDirection to determine right/left hand tap

CAM/Path/Post/scripts/linuxcnc_post.py
- Handle G84/G74 tapping cycles: convert pitch and spindle speed to feed rate
- Remove F and S from output and recalculate F as needed

CAM/Path/Tool/shape/models/tap.py
- Add Pitch property to ToolBitShapeTap schema
- CAM/Path/Tool/toolbit/models/tap.py
- Show pitch and rotation in tap tool summary
- Use is_imperial_pitch to format pitch as TPI or mm

CAM/Path/Tool/toolbit/util.py
- Add is_imperial_pitch utility to classify pitch as imperial or metric

CAM/Tools/Bit/375-16_Tap.fctb
- Remove unused parameters (Coating, Rotation, TPI, Type)
- Keep only relevant tap parameters for new schema

src/Mod/CAM/Tools/Bit/375-16_Tap.fctb

@@ -4,17 +4,13 @@
   "shape": "tap.fcstd",
   "shape-type": "tap",
   "parameter": {
-    "Coating": "None",
     "CuttingEdgeLength": "1.063 \"",
     "Diameter": "0.375 \"",
     "Flutes": "3",
     "Length": "2.500 \"",
     "Pitch": "0.000 in",
-    "Rotation": "Right Hand",
     "ShankDiameter": "0.250 \"",
-    "TPI": "16",
-    "TipAngle": "90.000 \u00b0",
-    "Type": "HSS"
+    "TipAngle": "90.000 \u00b0"
   },
   "attribute": {}
 }