Add API verification test suite and documentation

tests/docs/:
- API_FINDINGS.md: Comprehensive migration guide from deprecated to modern API
- test_*.py: 9 executable tests verifying actual runtime behavior
- screenshots/: Visual verification of working examples

tests/conftest.py:
- Add 'docs' and 'demo' to pytest collection paths

Key findings documented:
- Entity uses grid_pos= not pos=
- Scene API: Scene() + activate() replaces createScene/setScene
- scene.children replaces sceneUI()
- scene.on_key replaces keypressScene()
- mcrfpy.current_scene (property) replaces currentScene() (function)
- Timer callback signature: (timer, runtime)
- Opacity animation does NOT work on Frame (documented bug)

🤖 Generated with Claude Code (https://claude.ai/code)

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

tests/docs/test_features_scenes.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""Test for features/scenes.md examples.
+
+Tests both modern and procedural APIs from the docs.
+"""
+import mcrfpy
+from mcrfpy import automation
+import sys
+
+# Test 1: Modern Scene API (lines 28-42)
+print("Test 1: Modern Scene API")
+scene = mcrfpy.Scene("test_modern")
+scene.children.append(mcrfpy.Frame(pos=(0, 0), size=(800, 600)))
+
+def my_handler(key, action):
+    if action == "start":
+        print(f"  Key handler received: {key}")
+
+scene.on_key = my_handler
+scene.activate()
+mcrfpy.step(0.1)
+print("  PASS - modern Scene API works")
+
+# Test 2: Check Scene properties
+print("Test 2: Scene properties")
+print(f"  scene.name = {scene.name}")
+print(f"  scene.active = {scene.active}")
+print(f"  len(scene.children) = {len(scene.children)}")
+
+# Test 3: Check if default_texture exists
+print("Test 3: default_texture")
+try:
+    dt = mcrfpy.default_texture
+    print(f"  mcrfpy.default_texture = {dt}")
+except AttributeError:
+    print("  default_texture NOT FOUND - docs bug!")
+
+# Test 4: Check if currentScene exists
+print("Test 4: currentScene()")
+try:
+    current = mcrfpy.currentScene()
+    print(f"  mcrfpy.currentScene() = {current}")
+except AttributeError:
+    print("  currentScene() NOT FOUND - docs bug!")
+
+# Test 5: Check Grid.at() signature
+print("Test 5: Grid.at() signature")
+texture = mcrfpy.Texture("assets/kenney_tinydungeon.png", 16, 16)
+grid = mcrfpy.Grid(grid_size=(10, 10), texture=texture, pos=(0, 0), size=(200, 200))
+
+# Try both signatures
+try:
+    point_tuple = grid.at((5, 5))
+    print("  grid.at((x, y)) - tuple WORKS")
+except Exception as e:
+    print(f"  grid.at((x, y)) FAILS: {e}")
+
+try:
+    point_sep = grid.at(5, 5)
+    print("  grid.at(x, y) - separate args WORKS")
+except Exception as e:
+    print(f"  grid.at(x, y) FAILS: {e}")
+
+# Test 6: Scene transitions (setScene)
+print("Test 6: setScene()")
+scene2 = mcrfpy.Scene("test_transitions")
+scene2.activate()
+mcrfpy.step(0.1)
+
+# Check if setScene exists
+try:
+    mcrfpy.setScene("test_modern")
+    print("  mcrfpy.setScene() WORKS")
+except AttributeError:
+    print("  mcrfpy.setScene() NOT FOUND - use scene.activate() instead")
+except Exception as e:
+    print(f"  mcrfpy.setScene() error: {e}")
+
+# Take screenshot
+mcrfpy.step(0.1)
+automation.screenshot("/opt/goblincorps/repos/McRogueFace/tests/docs/screenshots/features_scenes.png")
+
+print("\nAll scene tests complete")
+sys.exit(0)