Clean up object naming

Honor the upstream names for objects if they've been given them, use
the automatic variable magic as a fallback.  And in the case of truly
anonymous objects, give them a name based on their type (e.g. "Box3")
vs. "_unknown_var99".

yacv_server/yacv.py

@@ -382,19 +382,30 @@ def _preprocess_cad(obj: CADLike, **kwargs) -> CADCoreLike:
     return obj
 
 
-_find_var_name_count = 0
-
+_obj_name_counts = {}
 
 def _find_var_name(obj: any, avoid_levels: int = 2) -> str:
     """A hacky way to get a stable name for an object that may change over time"""
-    global _find_var_name_count
+
+    # Build123d objects have a "label" property, CadQuery Assembly's have "name"
+    for f in ('label', 'name'):
+        if hasattr(obj, f):
+            v = getattr(obj, f)
+            if v != '':
+                return v;
+
+    # Otherwise walk up our stack to see if there's a local variable that points to it
     obj_shape = get_shape(obj, error=False) or obj
     for frame in inspect.stack()[avoid_levels:]:
         for key, value in frame.frame.f_locals.items():
             if get_shape(value, error=False) is obj_shape:
                 return key
-    _find_var_name_count += 1
-    return 'unknown_var_' + str(_find_var_name_count)
+
+    # Last resort, name it for its type with a disambiguating number
+    global _obj_name_counts
+    t = obj.__class__.__name__
+    _obj_name_counts[t] = 1 if t not in _obj_name_counts else _obj_name_counts[t] + 1
+    return t + str(_obj_name_counts[t])
 
 
 def sizeof_fmt(num, suffix="B"):