Python API improvements: Vectors, bounds, window singleton, hidden types

- #177: GridPoint.grid_pos property returns (x, y) tuple
- #179: Grid.grid_size returns Vector instead of tuple
- #181: Grid.center returns Vector instead of tuple
- #182: Caption.size/w/h read-only properties for text dimensions
- #184: mcrfpy.window singleton for window access
- #185: Removed get_bounds() method, use .bounds property instead
- #188: bounds/global_bounds return (pos, size) as pair of Vectors
- #189: Hide internal types from module namespace (iterators, collections)

Also fixed critical bug: Changed static PyTypeObject to inline in headers
to ensure single instance across translation units (was causing segfaults).

Closes #177, closes #179, closes #181, closes #182, closes #184, closes #185, closes #188, closes #189

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

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

tests/test_caption_size.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+"""Test Caption size/w/h properties"""
+import sys
+import mcrfpy
+
+print("Testing Caption size/w/h properties...")
+
+font = mcrfpy.Font("assets/JetbrainsMono.ttf")
+caption = mcrfpy.Caption(text="Test Caption", pos=(100, 100), font=font)
+print(f"Caption created: {caption}")
+
+# Test size property
+print("Testing size property...")
+size = caption.size
+print(f"size type: {type(size)}")
+print(f"size value: {size}")
+
+if not hasattr(size, 'x'):
+    print(f"FAIL: size should be Vector, got {type(size)}")
+    sys.exit(1)
+
+print(f"size.x={size.x}, size.y={size.y}")
+
+if size.x <= 0 or size.y <= 0:
+    print(f"FAIL: size should be positive, got ({size.x}, {size.y})")
+    sys.exit(1)
+
+# Test w property
+print("Testing w property...")
+w = caption.w
+print(f"w type: {type(w)}, value: {w}")
+
+if not isinstance(w, float):
+    print(f"FAIL: w should be float, got {type(w)}")
+    sys.exit(1)
+
+if w <= 0:
+    print(f"FAIL: w should be positive, got {w}")
+    sys.exit(1)
+
+# Test h property
+print("Testing h property...")
+h = caption.h
+print(f"h type: {type(h)}, value: {h}")
+
+if not isinstance(h, float):
+    print(f"FAIL: h should be float, got {type(h)}")
+    sys.exit(1)
+
+if h <= 0:
+    print(f"FAIL: h should be positive, got {h}")
+    sys.exit(1)
+
+# Verify w and h match size
+if abs(w - size.x) >= 0.001:
+    print(f"FAIL: w ({w}) should match size.x ({size.x})")
+    sys.exit(1)
+
+if abs(h - size.y) >= 0.001:
+    print(f"FAIL: h ({h}) should match size.y ({size.y})")
+    sys.exit(1)
+
+# Verify read-only
+print("Checking that size/w/h are read-only...")
+try:
+    caption.size = mcrfpy.Vector(100, 100)
+    print("FAIL: size should be read-only")
+    sys.exit(1)
+except AttributeError:
+    print("  size is correctly read-only")
+
+try:
+    caption.w = 100
+    print("FAIL: w should be read-only")
+    sys.exit(1)
+except AttributeError:
+    print("  w is correctly read-only")
+
+try:
+    caption.h = 100
+    print("FAIL: h should be read-only")
+    sys.exit(1)
+except AttributeError:
+    print("  h is correctly read-only")
+
+print("PASS: Caption size/w/h properties work correctly!")
+sys.exit(0)