fix: truncate article titles to safe UTF-8 budget

articles.py

@@ -56,15 +56,18 @@ def validate_images(body, directory):
             raise ValueError('配图为空或达到 20 MiB：' + target)
 
 
-def short_title(title, budget=80):
-    # Conservative UTF-16 budget: do not split astral characters / surrogate pairs.
-    if len(title.encode('utf-16-le')) // 2 <= budget:
+def short_title(title, budget=75):
+    """Keep a UTF-8 prefix within budget, adding three ASCII dots if shortened."""
+    if len(title.encode('utf-8')) <= budget or (title.endswith('...') and len(title.encode('utf-8')) <= budget + 3):
         return title
     out = ''
+    used = 0
     for ch in title:
-        if len((out + ch).encode('utf-16-le')) // 2 > budget - 3:
+        size = len(ch.encode('utf-8'))
+        if used + size > budget:
             break
         out += ch
+        used += size
     return out + '...'