fix: Update test files to use current API patterns

Migrates test suite to current API:
- Frame(x, y, w, h) → Frame(pos=(x, y), size=(w, h))
- Caption("text", x, y) → Caption(pos=(x, y), text="text")
- caption.size → caption.font_size
- Entity(x, y, ...) → Entity((x, y), ...)
- Grid(w, h, ...) → Grid(grid_size=(w, h), ...)
- cell.color → ColorLayer system

Tests now serve as valid API usage examples.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/unit/test_visual_path.py

@@ -4,28 +4,10 @@
 import mcrfpy
 import sys
 
-# Colors as tuples (r, g, b, a)
-WALL_COLOR = (60, 30, 30, 255)
-FLOOR_COLOR = (200, 200, 220, 255) 
-PATH_COLOR = (100, 255, 100, 255)
-
-def check_render(dt):
-    """Timer callback to verify rendering"""
-    print(f"\nTimer fired after {dt}ms")
-    
-    # Take screenshot
-    from mcrfpy import automation
-    automation.screenshot("visual_path_test.png")
-    print("Screenshot saved as visual_path_test.png")
-    
-    # Sample some path cells to verify colors
-    print("\nSampling path cell colors from grid:")
-    for x, y in [(1, 1), (2, 2), (3, 3)]:
-        cell = grid.at(x, y)
-        color = cell.color
-        print(f"  Cell ({x},{y}): color={color[:3]}")
-    
-    sys.exit(0)
+# Colors
+WALL_COLOR = mcrfpy.Color(60, 30, 30)
+FLOOR_COLOR = mcrfpy.Color(200, 200, 220)
+PATH_COLOR = mcrfpy.Color(100, 255, 100)
 
 # Create scene
 mcrfpy.createScene("visual_test")
@@ -34,20 +16,38 @@ mcrfpy.createScene("visual_test")
 grid = mcrfpy.Grid(grid_x=5, grid_y=5)
 grid.fill_color = mcrfpy.Color(0, 0, 0)
 
+# Add color layer for cell coloring
+color_layer = grid.add_layer("color", z_index=-1)
+
+def check_render(dt):
+    """Timer callback to verify rendering"""
+    print(f"\nTimer fired after {dt}ms")
+
+    # Take screenshot
+    from mcrfpy import automation
+    automation.screenshot("visual_path_test.png")
+    print("Screenshot saved as visual_path_test.png")
+
+    # Sample some path cells to verify colors
+    print("\nSampling path cell colors from grid:")
+    for x, y in [(1, 1), (2, 2), (3, 3)]:
+        color = color_layer.at(x, y)
+        print(f"  Cell ({x},{y}): color=({color.r}, {color.g}, {color.b})")
+
+    sys.exit(0)
+
 # Initialize all cells as floor
 print("Initializing grid...")
 for y in range(5):
     for x in range(5):
         grid.at(x, y).walkable = True
-        grid.at(x, y).color = FLOOR_COLOR
+        color_layer.set(x, y, FLOOR_COLOR)
 
 # Create entities
-e1 = mcrfpy.Entity(0, 0)
-e2 = mcrfpy.Entity(4, 4)
+e1 = mcrfpy.Entity((0, 0), grid=grid)
+e2 = mcrfpy.Entity((4, 4), grid=grid)
 e1.sprite_index = 64  # @
 e2.sprite_index = 69  # E
-grid.entities.append(e1)
-grid.entities.append(e2)
 
 print(f"Entity 1 at ({e1.x}, {e1.y})")
 print(f"Entity 2 at ({e2.x}, {e2.y})")
@@ -60,7 +60,7 @@ print(f"\nPath from E1 to E2: {path}")
 if path:
     print("\nColoring path cells green...")
     for x, y in path:
-        grid.at(x, y).color = PATH_COLOR
+        color_layer.set(x, y, PATH_COLOR)
         print(f"  Set ({x},{y}) to green")
 
 # Set up UI
@@ -70,7 +70,7 @@ grid.position = (50, 50)
 grid.size = (250, 250)
 
 # Add title
-title = mcrfpy.Caption("Path Visualization Test", 50, 10)
+title = mcrfpy.Caption(pos=(50, 10), text="Path Visualization Test")
 title.fill_color = mcrfpy.Color(255, 255, 255)
 ui.append(title)