fix: 统一时区处理，确保所有 datetime 带时区信息

- token_bucket.py: get_reset_time 和 Redis 后端使用 timezone.utc
- sliding_window.py: get_reset_time 和 retry_after 计算使用 timezone.utc
- provider_strategy.py: dateutil.parser 解析后确保有时区信息

src/api/admin/provider_strategy.py

@@ -2,7 +2,7 @@
 提供商策略管理 API 端点
 """
 
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from typing import Optional
 
 from fastapi import APIRouter, Depends, HTTPException, Request
@@ -103,6 +103,9 @@ class AdminProviderBillingAdapter(AdminApiAdapter):
 
         if config.quota_last_reset_at:
             new_reset_at = parser.parse(config.quota_last_reset_at)
+            # 确保有时区信息，如果没有则假设为 UTC
+            if new_reset_at.tzinfo is None:
+                new_reset_at = new_reset_at.replace(tzinfo=timezone.utc)
             provider.quota_last_reset_at = new_reset_at
 
             # 自动同步该周期内的历史使用量
@@ -118,7 +121,11 @@ class AdminProviderBillingAdapter(AdminApiAdapter):
             logger.info(f"Synced usage for provider {provider.name}: ${period_usage:.4f} since {new_reset_at}")
 
         if config.quota_expires_at:
-            provider.quota_expires_at = parser.parse(config.quota_expires_at)
+            expires_at = parser.parse(config.quota_expires_at)
+            # 确保有时区信息，如果没有则假设为 UTC
+            if expires_at.tzinfo is None:
+                expires_at = expires_at.replace(tzinfo=timezone.utc)
+            provider.quota_expires_at = expires_at
 
         db.commit()
         db.refresh(provider)
@@ -149,7 +156,7 @@ class AdminProviderStatsAdapter(AdminApiAdapter):
         if not provider:
             raise HTTPException(status_code=404, detail="Provider not found")
 
-        since = datetime.now() - timedelta(hours=self.hours)
+        since = datetime.now(timezone.utc) - timedelta(hours=self.hours)
         stats = (
             db.query(ProviderUsageTracking)
             .filter(

src/plugins/rate_limit/sliding_window.py

@@ -21,7 +21,7 @@ WARNING: 多进程环境注意事项
 import asyncio
 import time
 from collections import deque
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Any, Deque, Dict
 
 from src.core.logger import logger
@@ -95,12 +95,12 @@ class SlidingWindow:
         """获取最早的重置时间"""
         self._cleanup()
         if not self.requests:
-            return datetime.now()
+            return datetime.now(timezone.utc)
 
         # 最早的请求将在window_size秒后过期
         oldest_request = self.requests[0]
         reset_time = oldest_request + self.window_size
-        return datetime.fromtimestamp(reset_time)
+        return datetime.fromtimestamp(reset_time, tz=timezone.utc)
 
 
 class SlidingWindowStrategy(RateLimitStrategy):
@@ -250,7 +250,7 @@ class SlidingWindowStrategy(RateLimitStrategy):
             retry_after = None
             if not allowed:
                 # 计算需要等待的时间（最早请求过期的时间）
-                retry_after = int((reset_at - datetime.now()).total_seconds()) + 1
+                retry_after = int((reset_at - datetime.now(timezone.utc)).total_seconds()) + 1
 
             return RateLimitResult(
                 allowed=allowed,

src/plugins/rate_limit/token_bucket.py

@@ -3,7 +3,7 @@
 import asyncio
 import os
 import time
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from typing import Any, Dict, Optional, Tuple
 
 from ...clients.redis_client import get_redis_client_sync
@@ -63,11 +63,11 @@ class TokenBucket:
     def get_reset_time(self) -> datetime:
         """获取下次完全恢复的时间"""
         if self.tokens >= self.capacity:
-            return datetime.now()
+            return datetime.now(timezone.utc)
 
         tokens_needed = self.capacity - self.tokens
         seconds_to_full = tokens_needed / self.refill_rate
-        return datetime.now() + timedelta(seconds=seconds_to_full)
+        return datetime.now(timezone.utc) + timedelta(seconds=seconds_to_full)
 
 
 class TokenBucketStrategy(RateLimitStrategy):
@@ -370,7 +370,7 @@ class RedisTokenBucketBackend:
 
         if tokens is None or last_refill is None:
             remaining = capacity
-            reset_at = datetime.now() + timedelta(seconds=capacity / refill_rate)
+            reset_at = datetime.now(timezone.utc) + timedelta(seconds=capacity / refill_rate)
         else:
             tokens_value = float(tokens)
             last_refill_value = float(last_refill)
@@ -378,7 +378,7 @@ class RedisTokenBucketBackend:
             tokens_value = min(capacity, tokens_value + delta * refill_rate)
             remaining = int(tokens_value)
             reset_after = 0 if tokens_value >= capacity else (capacity - tokens_value) / refill_rate
-            reset_at = datetime.now() + timedelta(seconds=reset_after)
+            reset_at = datetime.now(timezone.utc) + timedelta(seconds=reset_after)
 
         allowed = remaining >= amount
         retry_after = None