feat: 重构为 Go Web 脚手架——在线图片识别 Web 服务 + vision-cli 独立工具

- Gin + config.yaml + SQLite 后端骨架，JWT 登录 + 管理员初始化
- web/ 原生单页：拖拽多图上传 → Agnes 免费识别 → 结果复制
- HTTP API：/api/v1/vision/analyze 免鉴权 + 令牌桶限流，支持程序直调
- cmd/vision-cli 独立 CLI 工具（复用 service 层，不依赖 Web 服务）
- build.bat / build.sh 构建脚本，移除 mcp-server
- 统一响应格式 {code, message, data}，CORS/JWT/限流中间件

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

internal/handler/auth_handler.go

@@ -0,0 +1,88 @@
+package handler
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+
+	"vision-tool/internal/model"
+	"vision-tool/internal/service"
+)
+
+// AuthHandler HTTP 处理器：管理员初始化 / 登录 / 用户信息。
+type AuthHandler struct {
+	svc *service.AuthService
+}
+
+func NewAuthHandler(svc *service.AuthService) *AuthHandler {
+	return &AuthHandler{svc: svc}
+}
+
+type initRequest struct {
+	Username string `json:"username" binding:"required,min=2,max=32"`
+	Password string `json:"password" binding:"required,min=6,max=64"`
+}
+
+type loginRequest struct {
+	Username string `json:"username" binding:"required"`
+	Password string `json:"password" binding:"required"`
+}
+
+// Check  GET /api/v1/admin/check — 管理员是否已初始化
+func (h *AuthHandler) Check(c *gin.Context) {
+	initialized, err := h.svc.CheckAdmin()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, model.Err(model.CodeServerErr, err.Error()))
+		return
+	}
+	c.JSON(http.StatusOK, model.OK(gin.H{"initialized": initialized}))
+}
+
+// Init  POST /api/v1/admin/init — 初始化管理员（仅首次）
+func (h *AuthHandler) Init(c *gin.Context) {
+	var req initRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, model.Err(model.CodeBadParam, "用户名 2-32 位，密码至少 6 位"))
+		return
+	}
+	if err := h.svc.InitAdmin(req.Username, req.Password); err != nil {
+		if errors.Is(err, service.ErrAdminExists) {
+			c.JSON(http.StatusConflict, model.Err(model.CodeConflict, err.Error()))
+			return
+		}
+		c.JSON(http.StatusInternalServerError, model.Err(model.CodeServerErr, err.Error()))
+		return
+	}
+	c.JSON(http.StatusOK, model.OK(gin.H{"message": "管理员初始化成功"}))
+}
+
+// Login  POST /api/v1/auth/login — 登录获取 JWT token
+func (h *AuthHandler) Login(c *gin.Context) {
+	var req loginRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, model.Err(model.CodeBadParam, "请输入用户名和密码"))
+		return
+	}
+	token, err := h.svc.Login(req.Username, req.Password)
+	if err != nil {
+		if errors.Is(err, service.ErrInvalidCredentials) {
+			c.JSON(http.StatusUnauthorized, model.Err(model.CodeUnauthorized, err.Error()))
+			return
+		}
+		c.JSON(http.StatusInternalServerError, model.Err(model.CodeServerErr, err.Error()))
+		return
+	}
+	c.JSON(http.StatusOK, model.OK(gin.H{"token": token}))
+}
+
+// Profile  GET /api/v1/user/profile — 当前用户信息（JWT 保护）
+func (h *AuthHandler) Profile(c *gin.Context) {
+	userID := c.GetUint("user_id")
+	user, err := h.svc.Profile(userID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, model.Err(model.CodeServerErr, err.Error()))
+		return
+	}
+	c.JSON(http.StatusOK, model.OK(user))
+}