feat(plugin): add centralized rating APIs

app/schemas/plugin.py

@@ -95,6 +95,26 @@ class PluginSidebarNavItem(BaseModel):
     order: int = Field(default=0, description="同组内排序，越小越靠前")
 
 
+class PluginRatingRequest(BaseModel):
+    """插件评分请求"""
+
+    rating: float = Field(
+        ge=0.1,
+        le=5.0,
+        multiple_of=0.1,
+        description="评分，范围 0.1 至 5.0，精确到 0.1",
+    )
+
+
+class PluginRating(BaseModel):
+    """插件评分结果"""
+
+    plugin_id: str = Field(description="插件 ID")
+    average_rating: float = Field(default=0.0, description="平均评分")
+    rating_count: int = Field(default=0, description="评分人数")
+    user_rating: Optional[float] = Field(default=None, description="当前安装实例评分")
+
+
 class PluginMemoryInfo(BaseModel):
     """插件内存信息"""
     plugin_id: str = Field(description="插件ID")