CAM: Add migration for Toolbit Units property

This PR adds migration for toolbit units by automatically infering the
Units (Metric/Imperial) from toolbit parameter strings and sets the
Units property if missing. It adds a utility function to detect units
from JSON. This is done at the JSON level during migration to ensure
that all toolbits have the correct Units property set.

src/Mod/CAM/Path/Tool/toolbit/migration.py:
- Infer Units from parameter strings if not set during migration
- Set Units property and log inference
- Refactor migration logic for clarity and reliability

src/Mod/CAM/Path/Tool/toolbit/models/base.py:
- Use Path.Log.debug instead of print when adding Units property

src/Mod/CAM/Path/Tool/toolbit/util.py:
- Add units_from_json() to infer Metric/Imperial from parameter strings

src/Mod/CAM/Path/Tool/toolbit/migration.py

@@ -25,6 +25,7 @@
 import FreeCAD
 import Path
 from typing import Dict, Any, Optional, Union
+from .util import units_from_json
 
 
 class ParameterAccessor:
@@ -74,9 +75,9 @@ class ParameterAccessor:
         else:
             self.target.setEditorMode(key, mode)
 
-    def label(self):
+    def name(self):
         if self.is_dict:
-            return "toolbit"
+            return self.target.get("name", "toolbit")
         else:
             return getattr(self.target, "Label", "unknown toolbit")
 
@@ -103,6 +104,7 @@ def migrate_parameters(accessor: ParameterAccessor) -> bool:
     Currently handles:
     - TorusRadius → CornerRadius
     - FlatRadius/Diameter → CornerRadius
+    - Infers Units from parameter strings if not set
 
     Args:
         accessor: ParameterAccessor instance wrapping dict or FreeCAD object
@@ -110,13 +112,28 @@ def migrate_parameters(accessor: ParameterAccessor) -> bool:
     Returns:
         True if migration occurred, False otherwise
     """
+    migrated = False
     has_torus = accessor.has("TorusRadius")
     has_flat = accessor.has("FlatRadius")
     has_diam = accessor.has("Diameter")
     has_corner = accessor.has("CornerRadius")
-    label = accessor.label()
+    has_units = accessor.has("Units")
+    name = accessor.name()
     shape_type = accessor.get_shape_type()
 
+    # Infer Units from parameter strings if not set
+    if not has_units:
+        # Gather all parameters to check for units
+        params = {}
+        if accessor.is_dict:
+            params = accessor.target.get("parameter", {})
+
+        inferred_units = units_from_json(params)
+        if inferred_units:
+            accessor.set("Units", inferred_units)
+            Path.Log.info(f"Adding Units as '{inferred_units}' for {name}")
+            migrated = True
+
     # Only run migration logic if shape type == 'Bullnose'
     if shape_type and str(shape_type).lower() == "bullnose":
         # Case 1: TorusRadius exists, copy to CornerRadius
@@ -130,11 +147,11 @@ def migrate_parameters(accessor: ParameterAccessor) -> bool:
             )
             accessor.set_editor_mode("CornerRadius", 0)
             accessor.set("CornerRadius", value)
-            Path.Log.info(f"Copied TorusRadius to CornerRadius={value} for {label}")
-            return True
+            Path.Log.info(f"Copied TorusRadius to CornerRadius={value} for {name}")
+            migrated = True
 
         # Case 2: FlatRadius and Diameter exist, calculate CornerRadius
-        if has_flat and has_diam and not has_corner:
+        if has_flat and has_diam and not has_corner and not has_torus:
             try:
                 diam_raw = accessor.get("Diameter")
                 flat_raw = accessor.get("FlatRadius")
@@ -161,10 +178,9 @@ def migrate_parameters(accessor: ParameterAccessor) -> bool:
                 )
                 accessor.set_editor_mode("CornerRadius", 0)
                 accessor.set("CornerRadius", value)
-                Path.Log.info(f"Migrated FlatRadius/Diameter to CornerRadius={value} for {label}")
-                return True
+                Path.Log.info(f"Migrated FlatRadius/Diameter to CornerRadius={value} for {name}")
+                migrated = True
             except Exception as e:
-                Path.Log.error(f"Failed to migrate FlatRadius for toolbit {label}: {e}")
-                return False
+                Path.Log.error(f"Failed to migrate FlatRadius for toolbit {name}: {e}")
 
-    return False
+    return migrated

src/Mod/CAM/Path/Tool/toolbit/models/base.py

@@ -793,7 +793,7 @@ class ToolBit(Asset, ABC):
 
         # 3. Ensure Units property exists and is set
         if not hasattr(self.obj, "Units"):
-            print("Adding Units property")
+            Path.Log.debug("Adding Units property")
             self.obj.addProperty(
                 "App::PropertyEnumeration",
                 "Units",

src/Mod/CAM/Path/Tool/toolbit/util.py

@@ -30,6 +30,49 @@ def to_json(value):
     return value
 
 
+def units_from_json(params):
+    """
+    Infer Units (Metric/Imperial) from JSON parameter strings.
+
+    For JSON files from disk, values are stored as strings like "3.175 in" or "6 mm".
+    This function examines common dimensional parameters (Diameter, Length, CuttingEdgeHeight, etc.)
+    to determine if the toolbit uses metric or imperial units.
+
+    Args:
+        params: Dictionary of parameters from JSON (before conversion to FreeCAD.Units.Quantity)
+
+    Returns:
+        str: "Metric" or "Imperial", or None if units cannot be determined
+    """
+    if not isinstance(params, dict):
+        return None
+
+    imperial_count = 0
+    metric_count = 0
+
+    for param_name in ("Diameter", "ShankDiameter", "Length", "CuttingEdgeLength"):
+        value = params.get(param_name)
+        if value is not None:
+            # Check if it's a string with unit suffix
+            if isinstance(value, str):
+                value_lower = value.lower().strip()
+
+                # Check for imperial units
+                if any(unit in value_lower for unit in ["in", "inch", '"', "thou"]):
+                    imperial_count += 1
+                # Check for metric units
+                elif any(unit in value_lower for unit in ["mm", "cm", "m "]):
+                    metric_count += 1
+
+        # Make a decision based on counts
+        if imperial_count > metric_count:
+            return "Imperial"
+        elif metric_count > imperial_count:
+            return "Metric"
+
+    return "Metric"  # Default to Metric if uncertain
+
+
 def format_value(
     value: FreeCAD.Units.Quantity | int | float | None,
     precision: int | None = None,