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/API_FINDINGS.md

@@ -0,0 +1,129 @@
+# McRogueFace API Test Findings
+*Generated by Frack, January 14, 2026*
+
+## Summary
+
+Tested code snippets from docs site against actual runtime API.
+Tests created in `/tests/docs/` with screenshots in `/tests/docs/screenshots/`.
+
+---
+
+## Entity Constructor
+
+**Correct:**
+```python
+entity = mcrfpy.Entity(grid_pos=(10, 7), texture=texture, sprite_index=84)
+```
+
+**Wrong:**
+```python
+entity = mcrfpy.Entity(pos=(10, 7), ...)  # FAILS - no 'pos' kwarg
+entity = mcrfpy.Entity(grid_x=10, grid_y=7, ...)  # FAILS - no separate kwargs
+```
+
+---
+
+## Scene API
+
+**Modern (WORKS):**
+```python
+scene = mcrfpy.Scene("name")
+scene.children.append(frame)
+scene.on_key = handler
+scene.activate()
+```
+
+**Deprecated → Modern:**
+```python
+# OLD                          → NEW
+mcrfpy.createScene("name")     → scene = mcrfpy.Scene("name")
+mcrfpy.sceneUI("name")         → scene.children
+mcrfpy.setScene("name")        → scene.activate()
+mcrfpy.keypressScene(fn)       → scene.on_key = fn
+mcrfpy.currentScene()          → mcrfpy.current_scene  # property, not function!
+```
+
+---
+
+## Grid.at() Signature
+
+Both work:
+```python
+point = grid.at((x, y))  # Tuple - documented
+point = grid.at(x, y)    # Separate args - also works!
+```
+
+---
+
+## Animation System
+
+**Works:**
+- `x`, `y`, `w`, `h` properties animate correctly
+- Callbacks fire as expected
+- Multiple simultaneous animations work
+- Easing functions work
+
+**Does NOT work:**
+- `opacity` - property exists, can set directly, but animation ignores it
+
+---
+
+## Timer API
+
+**Modern:**
+```python
+timer = mcrfpy.Timer("name", callback, seconds)
+# Callback signature: def callback(timer, runtime):
+```
+
+**Deprecated:**
+```python
+mcrfpy.setTimer("name", callback, milliseconds)  # Wrong signature too
+```
+
+---
+
+## Color API
+
+Always use `mcrfpy.Color()`:
+```python
+frame.fill_color = mcrfpy.Color(255, 0, 0)     # CORRECT
+frame.fill_color = mcrfpy.Color(255, 0, 0, 128)  # With alpha
+```
+
+Tuples no longer work:
+```python
+frame.fill_color = (255, 0, 0)  # FAILS
+```
+
+---
+
+## Available Globals
+
+**All exist:**
+- `mcrfpy.default_texture` - Texture for kenney_tinydungeon.png
+- `mcrfpy.default_font` - Font for JetBrains Mono
+- `mcrfpy.default_fov` - (default FOV settings)
+
+---
+
+## Files Requiring Updates
+
+1. `quickstart.md` - All 4 code blocks use deprecated API
+2. `features/scenes.md` - "Procedural API" section entirely deprecated
+3. `features/animation.md` - opacity examples don't work
+4. Any file using `setTimer`, `createScene`, `sceneUI`, `setScene`, `keypressScene`
+
+---
+
+## Test Files Created
+
+| Test | Status | Notes |
+|------|--------|-------|
+| test_quickstart_simple_scene.py | PASS | |
+| test_quickstart_main_menu.py | PASS | |
+| test_quickstart_entities.py | PASS | Uses grid_pos= |
+| test_quickstart_sprites.py | PASS | |
+| test_features_animation.py | PASS | opacity test skipped |
+| test_features_scenes.py | PASS | Documents deprecated API |
+| test_entity_api.py | INFO | Verifies grid_pos= works |