feat(sign_in): 新增独立每日签到插件，与抽卡签到共用同一份签到数据

- 群聊命令「签到」(别名: 每日签到/打卡)，白名单群聊或管理员可用
- 复用 xapi /bot/gacha/sign-in + /bot/points/add，与抽卡/WPF 共用 bot_gacha_daily_sign_in 表
- 积分随机 1-100，流水沿用 gacha_sign/抽卡签到；先到先得，重复签到提示已签到
- 新增 10 个单元测试，ruff 通过；更新 PLUGINS.md / README.md

danding_bot/plugins/danding_sign_in/__init__.py

@@ -0,0 +1,72 @@
+"""独立每日签到插件。
+
+用户发送「签到」即可完成每日签到并领取积分（每天一次）。
+与 onmyoji_gacha 抽卡签到、WPF 客户端签到共用 xapi `bot_gacha_daily_sign_in`
+签到数据：每天每用户仅一次，任一入口先到先得，后到者提示已签到。
+"""
+
+from nonebot import on_command, require
+from nonebot.adapters.onebot.v11 import Bot, GroupMessageEvent, MessageEvent
+from nonebot.plugin import PluginMetadata
+
+from .config import Config
+from .api import SignInAPI
+from .rules import check_permission
+from .service import perform_daily_sign_in
+
+require("danding_bot.plugins.danding_points")
+from danding_bot.plugins.danding_points import points_api  # noqa: E402
+
+__plugin_meta__ = PluginMetadata(
+    name="每日签到",
+    description="独立每日签到命令，与抽卡签到共用同一份签到数据",
+    usage="发送「签到」即可完成每日签到并领取积分（每天一次）",
+    type="application",
+    config=Config,
+    extra={
+        "required_plugins": ["danding_bot.plugins.danding_points"],
+    },
+)
+
+config = Config()
+sign_in_api = SignInAPI(config)
+
+sign_in_matcher = on_command("签到", aliases={"每日签到", "打卡"}, priority=5, rule=check_permission())
+
+
+@sign_in_matcher.handle()
+async def handle_sign_in(bot: Bot, event: MessageEvent):
+    user_id = str(event.user_id)
+    sender = event.sender
+    user_name = ""
+    if sender:
+        user_name = sender.card if isinstance(event, GroupMessageEvent) else sender.nickname
+    user_name = user_name or "用户"
+
+    result = await perform_daily_sign_in(
+        sign_in_api=sign_in_api,
+        points_api=points_api,
+        user_id=user_id,
+        points_min=config.SIGN_IN_POINTS_MIN,
+        points_max=config.SIGN_IN_POINTS_MAX,
+        source=config.SIGN_IN_SOURCE,
+        reason=config.SIGN_IN_REASON,
+    )
+
+    if not result["success"]:
+        await sign_in_matcher.finish(f"{user_name} ❌ {result['message']}")
+
+    if result["already_signed"]:
+        await sign_in_matcher.finish(
+            f"{user_name} 📅 今天已经签到过啦\n"
+            f"🎁 今日签到积分：{result['points']}\n"
+            f"（抽卡/WPF 签到同样计入每日一次）\n"
+            f"明天再来吧~"
+        )
+        return
+
+    await sign_in_matcher.finish(
+        f"{user_name} 📅 每日签到成功！\n"
+        f"🎁 获得积分：{result['points']}\n"
+        f"💰 当前积分：{result['balance']}"
+    )