surveyor: drop never used dead code

Surveyor test was failing because `get_z_rotation` and `set_z_rotation` were not implemented.
The code was added in 230cbe1fd8, but it was never used.

(cherry picked from commit 9e25c12b16)

src/bonsai/bonsai/core/product.py

@@ -1,65 +0,0 @@
-# Bonsai - OpenBIM Blender Add-on
-# Copyright (C) 2026
-#
-# This file is part of Bonsai.
-#
-# Bonsai is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Bonsai is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
-#
-# This file was generated with the assistance of an AI coding tool.
-
-from __future__ import annotations
-
-import math
-from collections.abc import Iterable
-from typing import TYPE_CHECKING
-
-import bonsai.core.geometry
-
-if TYPE_CHECKING:
-    import bpy
-
-    import bonsai.tool as tool
-
-
-Z_ROTATION_ALIGNMENT_TOLERANCE = 1e-9
-
-
-def _z_rotation_diff(target_z: float, source_z: float) -> float:
-    """Signed Z-Euler difference wrapped to [-π, π]."""
-    return (target_z - source_z + math.pi) % (2 * math.pi) - math.pi
-
-
-def copy_z_rotation_to_selected(
-    ifc: type[tool.Ifc],
-    geometry: type[tool.Geometry],
-    surveyor: type[tool.Surveyor],
-    *,
-    active: bpy.types.Object,
-    targets: Iterable[bpy.types.Object],
-    flip: bool = False,
-) -> int:
-    """Apply ``active``'s Z-Euler rotation to each target."""
-    source_z = surveyor.get_z_rotation(active)  # ty: ignore[missing-argument]
-    if flip:
-        source_z += math.pi
-    rotated = 0
-    for obj in targets:
-        target_z = surveyor.get_z_rotation(obj)  # ty: ignore[missing-argument]
-        if abs(_z_rotation_diff(target_z, source_z)) < Z_ROTATION_ALIGNMENT_TOLERANCE:
-            continue
-        surveyor.set_z_rotation(obj, source_z)  # ty: ignore[missing-argument]
-        rotated += 1
-        if ifc.get_entity(obj) is not None:
-            bonsai.core.geometry.edit_object_placement(ifc, geometry, surveyor, obj=obj)
-    return rotated