feat(ci): script checking;

scripts/thumbnail.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+import sys
+
+import numpy as np
+from PIL import Image
+
+if len(sys.argv) != 4:
+    print("Usage: python thumbnail.py <midnight.png> <daylight.png> <output.png>")
+    sys.exit(1)
+
+dark = Image.open(sys.argv[1]).convert("RGBA")
+light = Image.open(sys.argv[2]).convert("RGBA")
+
+if dark.size != light.size:
+    light = light.resize(dark.size, Image.Resampling.LANCZOS)
+
+width, height = dark.size
+mask = np.zeros((height, width), dtype=np.uint8)
+
+for y in range(height):
+    for x in range(width):
+        progress = (x + (height - y)) / (width + height)
+        mask[y, x] = int(progress * 255)
+
+mask_img = Image.fromarray(mask, mode="L")
+result = Image.composite(light, dark, mask_img)
+result.save(sys.argv[3], "PNG")
+
+print(f"✓ {sys.argv[3]} ({width}x{height})")