fix: disable thinking and extend timeout for filename translation

qwen3.6-plus on DashScope uses extended thinking by default, causing
filename translation to timeout at 10s (reasoning tokens add latency).
- enable_thinking: false → skip CoT for this simple one-word task
- timeout: 10 → 30s as safety net for slower environments

docutranslate/app.py

@@ -668,8 +668,9 @@ async def _translate_filename_stem(
                 "messages": [{"role": "user", "content": prompt}],
                 "max_tokens": 60,
                 "temperature": 0,
+                "enable_thinking": False,
             },
-            timeout=10,
+            timeout=30,
         )
         resp.raise_for_status()
         translated = resp.json()["choices"][0]["message"]["content"].strip().strip("\"'")