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_animation.py

@@ -0,0 +1,86 @@
+#!/usr/bin/env python3
+"""Test for features/animation.md examples.
+
+Tests the modern API equivalents of animation examples.
+"""
+import mcrfpy
+from mcrfpy import automation
+import sys
+
+# Setup scene using modern API
+scene = mcrfpy.Scene("animation_demo")
+scene.activate()
+mcrfpy.step(0.01)
+
+# Test 1: Basic Animation (lines 9-19)
+frame = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+frame.fill_color = mcrfpy.Color(255, 0, 0)
+scene.children.append(frame)
+
+# Animate x position
+anim = mcrfpy.Animation("x", 500.0, 2.0, "easeInOut")
+anim.start(frame)
+print("Test 1: Basic animation started")
+
+# Step forward to run animation
+mcrfpy.step(2.5)
+
+# Verify animation completed
+if abs(frame.x - 500.0) < 1.0:
+    print("Test 1: PASS - frame moved to x=500")
+else:
+    print(f"Test 1: FAIL - frame at x={frame.x}, expected 500")
+    sys.exit(1)
+
+# Test 2: Multiple simultaneous animations (lines 134-144)
+frame2 = mcrfpy.Frame(pos=(0, 0), size=(100, 100))
+frame2.fill_color = mcrfpy.Color(0, 255, 0)
+scene.children.append(frame2)
+
+mcrfpy.Animation("x", 200.0, 1.0, "easeInOut").start(frame2)
+mcrfpy.Animation("y", 150.0, 1.0, "easeInOut").start(frame2)
+mcrfpy.Animation("w", 300.0, 1.0, "easeInOut").start(frame2)
+mcrfpy.Animation("h", 200.0, 1.0, "easeInOut").start(frame2)
+
+mcrfpy.step(1.5)
+
+if abs(frame2.x - 200.0) < 1.0 and abs(frame2.y - 150.0) < 1.0:
+    print("Test 2: PASS - multiple animations completed")
+else:
+    print(f"Test 2: FAIL - frame2 at ({frame2.x}, {frame2.y})")
+    sys.exit(1)
+
+# Test 3: Callback (lines 105-112)
+callback_fired = False
+
+def on_complete(animation, target):
+    global callback_fired
+    callback_fired = True
+    print("Test 3: Callback fired!")
+
+frame3 = mcrfpy.Frame(pos=(0, 300), size=(50, 50))
+frame3.fill_color = mcrfpy.Color(0, 0, 255)
+scene.children.append(frame3)
+
+anim3 = mcrfpy.Animation("x", 300.0, 0.5, "easeInOut", callback=on_complete)
+anim3.start(frame3)
+
+mcrfpy.step(1.0)
+
+if callback_fired:
+    print("Test 3: PASS - callback executed")
+else:
+    print("Test 3: FAIL - callback not executed")
+    sys.exit(1)
+
+# Test 4: NOTE - Opacity animation documented in features/animation.md
+# but DOES NOT WORK on Frame. The property exists but animation
+# system doesn't animate it. This is a DOCS BUG to report.
+# Skipping test 4 - opacity animation not supported.
+print("Test 4: SKIPPED - opacity animation not supported on Frame (docs bug)")
+
+# Take screenshot showing animation results
+automation.screenshot("/opt/goblincorps/repos/McRogueFace/tests/docs/screenshots/features_animation.png")
+
+print("\nAll animation tests PASS")
+sys.exit(0)