Phase 4.2: Add GridView UIDrawable type (addresses #252)

GridView is a new UIDrawable that renders a GridData object independently.
Multiple GridViews can reference the same Grid for split-screen, minimap,
or different camera/zoom perspectives on shared grid state.

- New files: UIGridView.h/cpp with full rendering pipeline (copied from
  UIGrid::render, adapted to use grid_data pointer)
- Add UIGRIDVIEW to PyObjectsEnum
- Add UIGRIDVIEW cases to all switch(derived_type()) sites:
  Animation.cpp, UICollection.cpp, UIDrawable.cpp, McRFPy_API.cpp,
  ImGuiSceneExplorer.cpp
- Python type: mcrfpy.GridView(grid=, pos=, size=, zoom=, fill_color=)
- Properties: grid, center, zoom, fill_color, texture
- Register type with metaclass for callback support

All 258 existing tests pass. New GridView test suite added.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/unit/gridview_test.py

@@ -0,0 +1,91 @@
+"""Unit test for GridView (#252): rendering view for Grid data."""
+import mcrfpy
+import sys
+
+def test_gridview_creation():
+    """GridView can be created with a Grid reference."""
+    tex = mcrfpy.Texture("assets/kenney_tinydungeon.png", 16, 16)
+    grid = mcrfpy.Grid(grid_size=(10, 10), texture=tex, pos=(0, 0), size=(160, 160))
+    view = mcrfpy.GridView(grid=grid, pos=(200, 0), size=(160, 160))
+    assert view.zoom == 1.0
+    print("PASS: GridView creation")
+
+def test_gridview_properties():
+    """GridView properties can be read and set."""
+    tex = mcrfpy.Texture("assets/kenney_tinydungeon.png", 16, 16)
+    grid = mcrfpy.Grid(grid_size=(10, 10), texture=tex, pos=(0, 0), size=(160, 160))
+    view = mcrfpy.GridView(grid=grid, pos=(0, 0), size=(200, 200))
+
+    view.zoom = 2.0
+    assert abs(view.zoom - 2.0) < 0.01
+
+    view.center = (50, 50)
+    c = view.center
+    assert abs(c.x - 50) < 0.01 and abs(c.y - 50) < 0.01
+
+    view.fill_color = mcrfpy.Color(255, 0, 0)
+    assert view.fill_color.r == 255
+    print("PASS: GridView properties")
+
+def test_gridview_in_scene():
+    """GridView can be added to a scene's children."""
+    scene = mcrfpy.Scene("test_gv_scene")
+    mcrfpy.current_scene = scene
+
+    tex = mcrfpy.Texture("assets/kenney_tinydungeon.png", 16, 16)
+    grid = mcrfpy.Grid(grid_size=(10, 10), texture=tex, pos=(0, 0), size=(160, 160))
+    view = mcrfpy.GridView(grid=grid, pos=(200, 0), size=(160, 160))
+
+    scene.children.append(grid)
+    scene.children.append(view)
+    assert len(scene.children) == 2
+    print("PASS: GridView in scene")
+
+def test_gridview_multi_view():
+    """Multiple GridViews can reference the same Grid."""
+    scene = mcrfpy.Scene("test_gv_multi")
+    mcrfpy.current_scene = scene
+
+    tex = mcrfpy.Texture("assets/kenney_tinydungeon.png", 16, 16)
+    grid = mcrfpy.Grid(grid_size=(20, 20), texture=tex, pos=(0, 0), size=(320, 320))
+    scene.children.append(grid)
+
+    view1 = mcrfpy.GridView(grid=grid, pos=(350, 0), size=(160, 160), zoom=0.5)
+    view2 = mcrfpy.GridView(grid=grid, pos=(350, 170), size=(160, 160), zoom=2.0)
+
+    scene.children.append(view1)
+    scene.children.append(view2)
+
+    # Both views exist with different zoom
+    assert abs(view1.zoom - 0.5) < 0.01
+    assert abs(view2.zoom - 2.0) < 0.01
+    assert len(scene.children) == 3
+    print("PASS: Multiple GridViews of same Grid")
+
+def test_gridview_repr():
+    """GridView has useful repr."""
+    tex = mcrfpy.Texture("assets/kenney_tinydungeon.png", 16, 16)
+    grid = mcrfpy.Grid(grid_size=(15, 10), texture=tex, pos=(0, 0), size=(240, 160))
+    view = mcrfpy.GridView(grid=grid, pos=(0, 0), size=(240, 160))
+    r = repr(view)
+    assert "GridView" in r
+    assert "15x10" in r
+    print("PASS: GridView repr")
+
+def test_gridview_no_grid():
+    """GridView without a grid doesn't crash."""
+    view = mcrfpy.GridView()
+    assert view.grid is None
+    r = repr(view)
+    assert "None" in r
+    print("PASS: GridView without grid")
+
+if __name__ == "__main__":
+    test_gridview_creation()
+    test_gridview_properties()
+    test_gridview_in_scene()
+    test_gridview_multi_view()
+    test_gridview_repr()
+    test_gridview_no_grid()
+    print("All GridView tests passed")
+    sys.exit(0)