feat: ToNav-go v1.0.0 - 内部服务导航系统

功能:
- 前台导航: 分类Tab切换、实时搜索、健康状态指示、响应式适配
- 后台管理: 服务/分类CRUD、系统设置、登录认证(bcrypt)
- 健康检查: 定时检测(5min)、独立检查URL、三态指示(在线/离线/未检测)
- 云端备份: WebDAV上传/下载/恢复/删除、定时自动备份、本地备份管理

技术栈: Go + Gin + GORM + SQLite

handlers/views.go

@@ -0,0 +1,119 @@
+package handlers
+
+import (
+	"encoding/json"
+	"fmt"
+	"html/template"
+	"net/http"
+	"tonav-go/database"
+	"tonav-go/models"
+
+	"github.com/gin-contrib/sessions"
+	"github.com/gin-gonic/gin"
+)
+
+// AuthRequired 登录验证中间件
+func AuthRequired() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		session := sessions.Default(c)
+		userID := session.Get("user_id")
+		if userID == nil {
+			c.Redirect(http.StatusFound, "/admin/login")
+			c.Abort()
+			return
+		}
+
+		mustChange := session.Get("must_change")
+		if mustChange == true && c.Request.URL.Path != "/admin/change-password" && c.Request.URL.Path != "/admin/logout" {
+			c.Redirect(http.StatusFound, "/admin/change-password")
+			c.Abort()
+			return
+		}
+		c.Next()
+	}
+}
+
+// DashboardHandler 渲染后台首页
+func DashboardHandler(c *gin.Context) {
+	var serviceCount, categoryCount int64
+	var onlineCount, offlineCount int64
+	database.DB.Model(&models.Service{}).Count(&serviceCount)
+	database.DB.Model(&models.Category{}).Count(&categoryCount)
+	database.DB.Model(&models.Service{}).Where("status = ?", "online").Count(&onlineCount)
+	database.DB.Model(&models.Service{}).Where("status = ?", "offline").Count(&offlineCount)
+
+	c.HTML(http.StatusOK, "dashboard.html", gin.H{
+		"service_count":  serviceCount,
+		"category_count": categoryCount,
+		"online_count":   onlineCount,
+		"offline_count":  offlineCount,
+	})
+}
+
+// IndexHandler 渲染前台首页
+func IndexHandler(c *gin.Context) {
+	if database.DB == nil {
+		c.String(http.StatusInternalServerError, "DB NIL")
+		return
+	}
+
+	// 获取所有分类
+	var categories []models.Category
+	database.DB.Order("sort_order desc").Find(&categories)
+
+	// 获取所有启用的服务
+	var services []models.Service
+	database.DB.Where("is_enabled = ?", true).Order("category_id asc, sort_order desc").Find(&services)
+
+	// 获取站点标题设置
+	var titleSetting models.Setting
+	siteTitle := "ToNav"
+	if err := database.DB.Where("key = ?", "site_title").First(&titleSetting).Error; err == nil && titleSetting.Value != "" {
+		siteTitle = titleSetting.Value
+	}
+
+	// 序列化为 JSON 供前端 JS 使用
+	categoriesJSON, _ := json.Marshal(categories)
+	servicesJSON, _ := json.Marshal(services)
+
+	c.HTML(http.StatusOK, "index.html", gin.H{
+		"site_title":      siteTitle,
+		"categories":      categories,
+		"categories_json": template.JS(categoriesJSON),
+		"services_json":   template.JS(servicesJSON),
+	})
+}
+
+// ServicesPageHandler 渲染服务管理页面
+func ServicesPageHandler(c *gin.Context) {
+	var categories []models.Category
+	database.DB.Order("sort_order desc").Find(&categories)
+	c.HTML(http.StatusOK, "services.html", gin.H{
+		"categories": categories,
+	})
+}
+
+// CategoriesPageHandler 渲染分类管理页面
+func CategoriesPageHandler(c *gin.Context) {
+	c.HTML(http.StatusOK, "categories.html", nil)
+}
+
+// getSessionUserID 安全获取 session 中的 user_id
+func getSessionUserID(session sessions.Session) (uint, error) {
+	userID := session.Get("user_id")
+	if userID == nil {
+		return 0, fmt.Errorf("user not logged in")
+	}
+	switch v := userID.(type) {
+	case uint:
+		return v, nil
+	case int:
+		return uint(v), nil
+	case int64:
+		return uint(v), nil
+	case float64:
+		return uint(v), nil
+	default:
+		return 0, fmt.Errorf("unexpected user_id type: %T", userID)
+	}
+}