fix: 禁止日志缓存，确保所有日志立刻输出

- scripts/*.sh: PYTHONUNBUFFERED=1
- tools/generate_questions.py: loguru file sink enqueue=False
- main.py: loguru file sink enqueue=False

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

scripts/generate_questions.sh

@@ -17,6 +17,9 @@ export CUDA_VISIBLE_DEVICES
 export HF_HUB_OFFLINE=1
 export TRANSFORMERS_OFFLINE=1
 
+# 禁止任何形式的日志缓存，确保所有日志立刻输出
+export PYTHONUNBUFFERED=1
+
 # 加载环境变量（API key 等）
 set -a
 source .env