Fix ai_ext.py fallback: return empty instead of echoing prompt

ai_ext.py

@@ -174,39 +174,9 @@ async def qwen_generate(prompt: str, image_url: str = None, max_tokens: int = 12
 
 
 def _fallback_summary_from_prompt(prompt: str, max_units: int = 6) -> str:
-    """Generate a simple fallback summary when AI is unavailable."""
-    text = prompt or ""
-    for marker in ["Nội dung nguồn:", "Nội dung bài:", "Nội dung gốc:", "Nội dung:", "Nguồn/bối cảnh internet:"]:
-        if marker in text:
-            text = text.split(marker, 1)[1]
-            break
-    text = re.sub(r"https?://\S+", "", text)
-    text = re.sub(r"\s+", " ", text).strip()
-    
-    # Split into sentences - extract ALL valid sentences, not just first few
-    sentences = re.split(r"(?<=[.!?])\s+(?=[A-ZÀ-Ỹ0-9])", text)
-    units = []
-    for s in sentences:
-        s = _clean_text(s)
-        if len(s) >= 30:  # Lower threshold to capture more content
-            units.append(s)
-    
-    if units:
-        # Take up to max_units valid sentences
-        result_units = units[:max_units]
-        return "\n".join("• " + u for u in result_units)
-    if text:
-        # Fallback: take chunks if no sentence boundaries found
-        chunks = []
-        for i in range(0, min(len(text), max_units * 300), 280):
-            chunk = _clean_text(text[i:i+300])
-            if chunk and chunk not in chunks:
-                chunks.append(chunk)
-                if len(chunks) >= max_units:
-                    break
-        if chunks:
-            return "\n".join("• " + c for c in chunks)
-    return "• Không có đủ nội dung để tóm tắt."
+    """Generate a simple fallback summary when AI is unavailable.
+    Returns empty string so callers can provide their own fallback."""
+    return ""
 
 
 HF_TOKEN = _hf_token()