chore(dev): add Pillow compatibility smoke test script

Covers all Pillow APIs used in LEDMatrix — image creation, drawing,
font metrics, LANCZOS resampling, paste/alpha_composite, and PNG I/O.
Run after any Pillow version bump to catch regressions before deploy.

    python3 scripts/dev/test_pillow_compat.py

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

scripts/dev/test_pillow_compat.py

@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+"""
+Pillow compatibility smoke test.
+
+Exercises the Pillow APIs used throughout LEDMatrix to verify a new
+Pillow version doesn't break image rendering, font handling, or resize ops.
+
+Run after upgrading Pillow:
+    python3 scripts/dev/test_pillow_compat.py
+"""
+
+import sys
+
+
+def check(label, fn):
+    try:
+        result = fn()
+        print(f"  ✓ {label}" + (f" — {result}" if result is not None else ""))
+        return True
+    except Exception as e:
+        print(f"  ✗ {label} — {type(e).__name__}: {e}", file=sys.stderr)
+        return False
+
+
+def main():
+    from PIL import Image, ImageDraw, ImageFont, ImageFilter
+    import PIL
+
+    print(f"Pillow {PIL.__version__} on Python {sys.version.split()[0]}\n")
+
+    failures = 0
+
+    print("Image creation:")
+    failures += not check("Image.new RGB",
+        lambda: Image.new('RGB', (128, 32), (0, 0, 0)).size)
+    failures += not check("Image.new RGBA",
+        lambda: Image.new('RGBA', (64, 64), (255, 0, 0, 128)).size)
+    failures += not check("Image.new 1-bit",
+        lambda: Image.new('1', (16, 16)).size)
+
+    print("\nDraw operations:")
+    img = Image.new('RGB', (128, 32), (0, 0, 0))
+    draw = ImageDraw.Draw(img)
+    font = ImageFont.load_default()
+    failures += not check("draw.rectangle",
+        lambda: draw.rectangle([0, 0, 127, 31], outline=(255, 0, 0)))
+    failures += not check("draw.text",
+        lambda: draw.text((2, 2), "Hello", fill=(255, 255, 255), font=font))
+    failures += not check("draw.line",
+        lambda: draw.line([0, 0, 127, 31], fill=(0, 255, 0)))
+
+    print("\nFont metrics (used in text_helper, scroll_helper):")
+    failures += not check("draw.textlength",
+        lambda: f"{draw.textlength('Test', font=font):.1f}px")
+    failures += not check("draw.textbbox",
+        lambda: draw.textbbox((0, 0), "Test", font=font))
+
+    print("\nResampling (used in logo_helper, image_utils, sports base):")
+    logo = Image.new('RGBA', (200, 200), (255, 128, 0, 200))
+    failures += not check("Image.Resampling.LANCZOS exists",
+        lambda: str(Image.Resampling.LANCZOS))
+    failures += not check("thumbnail with LANCZOS",
+        lambda: (logo.thumbnail((64, 32), Image.Resampling.LANCZOS), logo.size)[1])
+    big = Image.new('RGB', (300, 300), (0, 128, 255))
+    failures += not check("resize with LANCZOS",
+        lambda: big.resize((128, 32), Image.Resampling.LANCZOS).size)
+
+    print("\nComposite / paste (used in display rendering):")
+    base = Image.new('RGB', (128, 32), (0, 0, 0))
+    overlay = Image.new('RGBA', (32, 32), (255, 0, 0, 128))
+    failures += not check("paste RGBA onto RGB",
+        lambda: (base.paste(overlay.convert('RGB'), (0, 0)), base.size)[1])
+    failures += not check("Image.alpha_composite",
+        lambda: Image.alpha_composite(
+            Image.new('RGBA', (32, 32)), overlay).size)
+
+    print("\nImage I/O:")
+    import io
+    buf = io.BytesIO()
+    img.save(buf, format='PNG')
+    buf.seek(0)
+    failures += not check("save/load PNG roundtrip",
+        lambda: Image.open(buf).size)
+
+    print()
+    if failures == 0:
+        print(f"All checks passed. Pillow {PIL.__version__} is compatible.")
+        return 0
+    else:
+        print(f"{failures} check(s) failed — review output above.", file=sys.stderr)
+        return 1
+
+
+if __name__ == '__main__':
+    sys.exit(main())