feat: 品牌重命名 Sub2API -> TianShuAPI

- 前端: 所有界面显示、i18n 文本、组件中的品牌名称
- 后端: 服务层、设置默认值、邮件模板、安装向导
- 数据库: 迁移脚本注释
- 保持功能完全一致，仅更改品牌名称

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

backend/internal/server/middleware/cors.go

@@ -1,24 +1,24 @@
-package middleware
-
-import (
-	"github.com/gin-gonic/gin"
-)
-
-// CORS 跨域中间件
-func CORS() gin.HandlerFunc {
-	return func(c *gin.Context) {
-		// 设置允许跨域的响应头
-		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
-		c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
-		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With, X-API-Key")
-		c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS, GET, PUT, DELETE, PATCH")
-
-		// 处理预检请求
-		if c.Request.Method == "OPTIONS" {
-			c.AbortWithStatus(204)
-			return
-		}
-
-		c.Next()
-	}
-}
+package middleware
+
+import (
+	"github.com/gin-gonic/gin"
+)
+
+// CORS 跨域中间件
+func CORS() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// 设置允许跨域的响应头
+		c.Writer.Header().Set("Access-Control-Allow-Origin", "*")
+		c.Writer.Header().Set("Access-Control-Allow-Credentials", "true")
+		c.Writer.Header().Set("Access-Control-Allow-Headers", "Content-Type, Content-Length, Accept-Encoding, X-CSRF-Token, Authorization, accept, origin, Cache-Control, X-Requested-With, X-API-Key")
+		c.Writer.Header().Set("Access-Control-Allow-Methods", "POST, OPTIONS, GET, PUT, DELETE, PATCH")
+
+		// 处理预检请求
+		if c.Request.Method == "OPTIONS" {
+			c.AbortWithStatus(204)
+			return
+		}
+
+		c.Next()
+	}
+}