refactor(page): delete the dead child-measurement helpers (R6)

page.py carried a closed cluster of five methods with no callers outside
itself:

    _get_child_property   called only by the four below
    _get_child_height     called by nothing
    _get_child_position   called only by _point_in_child
    _point_in_child       called by nothing
    _get_child_size       called only by _point_in_child

138 lines, verified unreferenced across pyWebLayout/, tests/, examples/
and scripts/.

They existed because Renderable declares no size, so the code probed
_size, size, _height, height, _origin and position in turn with hasattr,
guessing at each child's shape. query_point already does the right thing
instead: it hit-tests through the Queriable interface.

Hardening the Renderable contract so this cannot grow back - Renderable
has origin but no size - belongs with S10.1, which is already going to
revisit the render contract in core/base.py. Left alone here rather than
half-done.

894 passed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

pyWebLayout/concrete/page.py

@@ -258,69 +258,6 @@ class Page(Renderable, Queriable):
         """Get a copy of the children list"""
         return self._children.copy()
 
-    def _get_child_property(self, child: Renderable, private_attr: str,
-                            public_attr: str, index: Optional[int] = None,
-                            default: Optional[int] = None) -> Optional[int]:
-        """
-        Generic helper to extract properties from child objects with multiple fallback strategies.
-
-        Args:
-            child: The child object
-            private_attr: Name of the private attribute (e.g., '_size')
-            public_attr: Name of the public property (e.g., 'size')
-            index: Optional index for array-like properties (0 for width, 1 for height)
-            default: Default value if property cannot be determined
-
-        Returns:
-            Property value or default
-        """
-        # Try private attribute first
-        if hasattr(child, private_attr):
-            value = getattr(child, private_attr)
-            if value is not None:
-                if isinstance(value, (list, tuple, np.ndarray)):
-                    if index is not None and len(value) > index:
-                        return int(value[index])
-                    elif index is None:
-                        return value
-
-        # Try public property
-        if hasattr(child, public_attr):
-            value = getattr(child, public_attr)
-            if value is not None:
-                if isinstance(value, (list, tuple, np.ndarray)):
-                    if index is not None and len(value) > index:
-                        return int(value[index])
-                    elif index is None:
-                        return value
-                else:
-                    return int(value)
-
-        return default
-
-    def _get_child_height(self, child: Renderable) -> int:
-        """
-        Get the height of a child object.
-
-        Args:
-            child: The child to measure
-
-        Returns:
-            Height in pixels
-        """
-        # Try to get height from size property (index 1)
-        height = self._get_child_property(child, '_size', 'size', index=1)
-        if height is not None:
-            return height
-
-        # Try direct height attribute
-        height = self._get_child_property(child, '_height', 'height')
-        if height is not None:
-            return height
-
-        # Default fallback height
-        return 20
-
     def render_children(self):
         """
         Call render on all children in the list.
@@ -379,23 +316,6 @@ class Page(Renderable, Queriable):
 
         return canvas
 
-    def _get_child_position(self, child: Renderable) -> Tuple[int, int]:
-        """
-        Get the position where a child should be rendered.
-
-        Args:
-            child: The child object
-
-        Returns:
-            Tuple of (x, y) coordinates
-        """
-        # Try to get x coordinate
-        x = self._get_child_property(child, '_origin', 'position', index=0, default=0)
-        # Try to get y coordinate
-        y = self._get_child_property(child, '_origin', 'position', index=1, default=0)
-
-        return (x, y)
-
     def query_point(self, point: Tuple[int, int]) -> Optional[QueryResult]:
         """
         Query a point to find the deepest object at that location.
@@ -432,64 +352,6 @@ class Page(Renderable, Queriable):
             bounds=(int(point[0]), int(point[1]), 0, 0)
         )
 
-    def _point_in_child(self, point: np.ndarray, child: Renderable) -> bool:
-        """
-        Check if a point is within a child's bounds.
-
-        Args:
-            point: The point to check
-            child: The child to check against
-
-        Returns:
-            True if the point is within the child's bounds
-        """
-        # If child implements Queriable interface, use it
-        if isinstance(child, Queriable) and hasattr(child, 'in_object'):
-            try:
-                return child.in_object(point)
-            except BaseException:
-                pass  # Fall back to bounds checking
-
-        # Get child position and size for bounds checking
-        child_pos = self._get_child_position(child)
-        child_size = self._get_child_size(child)
-
-        if child_size is None:
-            return False
-
-        # Check if point is within child bounds
-        return (
-            child_pos[0] <= point[0] < child_pos[0] + child_size[0] and
-            child_pos[1] <= point[1] < child_pos[1] + child_size[1]
-        )
-
-    def _get_child_size(self, child: Renderable) -> Optional[Tuple[int, int]]:
-        """
-        Get the size of a child object.
-
-        Args:
-            child: The child to measure
-
-        Returns:
-            Tuple of (width, height) or None if size cannot be determined
-        """
-        # Try to get width and height from size property
-        width = self._get_child_property(child, '_size', 'size', index=0)
-        height = self._get_child_property(child, '_size', 'size', index=1)
-
-        # If size property worked, return it
-        if width is not None and height is not None:
-            return (width, height)
-
-        # Try direct width/height attributes
-        width = self._get_child_property(child, '_width', 'width')
-        height = self._get_child_property(child, '_height', 'height')
-
-        if width is not None and height is not None:
-            return (width, height)
-
-        return None
-
     def _make_query_result(self, obj, point: Tuple[int, int]) -> QueryResult:
         """
         Package an object into a QueryResult with metadata.