功能：实现 Group_Horse_Racing 群赛马插件

- 新增群赛马游戏插件，支持多人参与赛马竞猜

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

danding_bot/plugins/group_horse_racing/points_service.py

@@ -0,0 +1,63 @@
+from typing import Tuple
+from danding_bot.plugins.danding_points import points_api
+from .config import Config
+
+
+class PointsService:
+    def __init__(self, config: Config):
+        self.config = config
+
+    async def spend_bet_points(
+        self, user_id: str, amount: int, reason: str = "赛马下注"
+    ) -> Tuple[bool, int]:
+        """Deduct points for betting with retry."""
+        success, balance = await points_api.spend_points(
+            user_id, amount, "horse_race", reason
+        )
+        if not success:
+            success, balance = await points_api.spend_points(
+                user_id, amount, "horse_race", reason
+            )
+        return success, balance
+
+    async def refund_bet_points(
+        self, user_id: str, amount: int, reason: str = "取消报名退还"
+    ) -> Tuple[bool, int]:
+        """Refund bet points."""
+        return await points_api.add_points(user_id, amount, "horse_race", reason)
+
+    async def payout_winnings(
+        self, user_id: str, amount: int, odds: float
+    ) -> Tuple[bool, int]:
+        """Payout bet winnings."""
+        payout = int(amount * odds)
+        reason = f"下注获胜 ×{odds:.2f}"
+        return await points_api.add_points(user_id, payout, "horse_race", reason)
+
+    async def reward_participant(self, user_id: str) -> Tuple[bool, int]:
+        """Reward race participant."""
+        return await points_api.add_points(
+            user_id,
+            self.config.PARTICIPANT_REWARD,
+            "horse_race",
+            "参赛奖励",
+        )
+
+    async def reward_champion(self, user_id: str) -> Tuple[bool, int]:
+        """Reward race champion."""
+        return await points_api.add_points(
+            user_id,
+            self.config.CHAMPION_REWARD,
+            "horse_race",
+            "冠军奖励",
+        )
+
+    async def set_points(
+        self, user_id: str, amount: int, reason: str = "测试设置积分"
+    ) -> Tuple[bool, int]:
+        """Set user points (for testing)."""
+        return await points_api.set_points(user_id, amount, "horse_race", reason)
+
+    async def get_balance(self, user_id: str) -> int:
+        """Get user balance."""
+        return await points_api.get_balance(user_id)