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/integration/simple_interactive_visibility.py

@@ -11,6 +11,9 @@ mcrfpy.createScene("vis_test")
 print("Creating grid...")
 grid = mcrfpy.Grid(grid_x=10, grid_y=10)
 
+# Add color layer for cell coloring
+color_layer = grid.add_layer("color", z_index=-1)
+
 # Initialize grid
 print("Initializing grid...")
 for y in range(10):
@@ -18,11 +21,11 @@ for y in range(10):
         cell = grid.at(x, y)
         cell.walkable = True
         cell.transparent = True
-        cell.color = mcrfpy.Color(100, 100, 120)
+        color_layer.set(x, y, mcrfpy.Color(100, 100, 120))
 
 # Create entity
 print("Creating entity...")
-entity = mcrfpy.Entity(5, 5, grid=grid)
+entity = mcrfpy.Entity((5, 5), grid=grid)
 entity.sprite_index = 64
 
 print("Updating visibility...")