Migrate Modifier shim callers + drop the shim block

Completes the PR4/PR5 cleanup the FIXME at tool/blender.py
flagged: every is_<type> / Array.<helper> shim on
tool.Blender.Modifier delegated one-for-one to tool.Parametric /
tool.Array. Callers now reach the canonical home directly, and the
shim block — seven is_<type> classmethods plus the inner class Array
— comes out.

Renames (no semantic change):

* tool.Blender.Modifier.is_<door|railing|roof|stair|wall|window>
  → tool.Parametric.is_<x>
  13 sites across tool/loader.py, bim/import_ifc.py,
  bim/module/geometry/{data,operator}.py, bim/module/model/{door,
  railing,roof,stair,ui,wall,window}.py.

* tool.Blender.Modifier.Array.<helper> → tool.Array.<helper>
  4 sites across tool/root.py, bim/import_ifc.py,
  bim/module/geometry/operator.py.

* test_parametric_registry.py: the two getattr probes that hunt
  predicates by name now look on tool.Parametric. Docstring + the
  test function name (test_every_entry_has_modifier_predicate →
  test_every_entry_has_parametric_predicate) follow the move.

Kept on tool.Blender.Modifier (non-shim, no equivalent on
tool.Parametric): try_applying_edit_mode,
try_canceling_editing_modifier_parameters_or_path,
is_eligible_for_<x>_modifier (×5), is_array_child, is_slab.

Verified: 109 model-lane tests + 8 parametric-registry tests pass
(the one pre-existing failure in test_wall_header_refresh.py is
unrelated — it patches handler.update_bim_tool_props which has been
renamed). git grep for tool\.Blender\.Modifier\.(is_<type>|Array\.)
returns empty. black + ruff clean on every touched file.

Generated with the assistance of an AI coding tool.

src/bonsai/test/bim/test_parametric_registry.py

@@ -30,7 +30,7 @@ will ship.
 These tests pin the registry-to-runtime contract: for every entry the operator
 ``bl_idname``s resolve to registered ``bpy.ops.bim.*`` callables, the
 ``PropertyGroup`` class is attached to ``bpy.types.Object``, and the per-type
-predicate exists on `tool.Blender.Modifier`."""
+predicate exists on `tool.Parametric`."""
 
 import types
 
@@ -82,11 +82,11 @@ def test_every_entry_has_property_group_attached(registry):
     )
 
 
-def test_every_entry_has_modifier_predicate(registry):
+def test_every_entry_has_parametric_predicate(registry):
     from bonsai import tool
 
-    missing = [e.name for e in registry if getattr(tool.Blender.Modifier, f"is_{e.name}", None) is None]
-    assert not missing, f"tool.Blender.Modifier missing is_<name> predicates: {missing}"
+    missing = [e.name for e in registry if getattr(tool.Parametric, f"is_{e.name}", None) is None]
+    assert not missing, f"tool.Parametric missing is_<name> predicates: {missing}"
 
 
 def test_every_predicate_does_not_raise_on_non_matching_element(registry):
@@ -109,7 +109,7 @@ def test_every_predicate_does_not_raise_on_non_matching_element(registry):
 
     raised = []
     for feature in registry:
-        predicate = getattr(tool.Blender.Modifier, f"is_{feature.name}", None)
+        predicate = getattr(tool.Parametric, f"is_{feature.name}", None)
         if predicate is None:
             continue
         try: