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/config.py

@@ -0,0 +1,78 @@
+"""独立每日签到插件 - 配置。
+
+与 onmyoji_gacha 抽卡插件共用同一 xapi 服务（/bot/gacha）与鉴权配置，
+签到数据天然共用 xapi `bot_gacha_daily_sign_in` 表。
+"""
+
+from pydantic import Field, field_validator
+from pydantic_settings import BaseSettings, SettingsConfigDict
+import os
+
+
+def _read_nonebot_config(name: str) -> str:
+    """从 NoneBot driver.config 读取配置；测试或独立加载模块时静默回退。"""
+
+    try:
+        from nonebot import get_driver
+
+        driver_config = get_driver().config
+    except Exception:
+        return ""
+    value = getattr(driver_config, name.lower(), "")
+    return str(value) if value is not None else ""
+
+
+def _read_setting(name: str) -> str:
+    """按单个配置名读取系统环境变量，再读取 NoneBot 配置对象。"""
+
+    return os.getenv(name, "") or _read_nonebot_config(name)
+
+
+def _first_setting(*names: str, default: str = "") -> str:
+    """按业务优先级读取多个兼容配置名。"""
+
+    for name in names:
+        value = _read_setting(name)
+        if value:
+            return value
+    return default
+
+
+class Config(BaseSettings):
+    model_config = SettingsConfigDict(extra="ignore")
+
+    # xapi /bot/gacha 运行时 API 配置（与 onmyoji_gacha 共用同一服务与鉴权）
+    GACHA_API_HOST: str = Field(
+        default_factory=lambda: _first_setting(
+            "DANDING_GACHA_API_HOST",
+            default="https://api.danding.vip/bot/gacha",
+        )
+    )
+    BOT_TOKEN: str = Field(
+        default_factory=lambda: _first_setting(
+            "DANDING_BOT_TOKEN",
+            "ONMYOJI_BOT_TOKEN",
+            "DANDING_API_TOKEN",
+            "BOT_TOKEN",
+        )
+    )
+    BOT_USER_ID: str = Field(default_factory=lambda: _first_setting("DANDING_BOT_USER", default="1424473282"))
+
+    # 权限：白名单群聊 + 管理员
+    ALLOWED_GROUP_ID: int = 621016172
+    ALLOWED_USER_ID: int = 1424473282
+
+    # 签到积分区间（与抽卡签到一致：随机 1-100）
+    SIGN_IN_POINTS_MIN: int = 1
+    SIGN_IN_POINTS_MAX: int = 100
+
+    # 积分流水标记（与抽卡/WPF 签到共用同一事件语义，保持流水一致）
+    SIGN_IN_SOURCE: str = "gacha_sign"
+    SIGN_IN_REASON: str = "抽卡签到"
+
+    @field_validator("GACHA_API_HOST")
+    @classmethod
+    def validate_gacha_api_host(cls, value):
+        if not value:
+            raise ValueError("GACHA_API_HOST cannot be empty")
+        return value.rstrip("/")