feat: 实现积分与等级系统 + 签到功能 + 下拉菜单优化

- User 模型增加 exp 字段，等级规则 Lv0-Lv6
- 新增签到记录(UserCheckIn)与任务记录(UserTask)模型，唯一索引防重
- 自动签到：AuthMiddleware 验证会话后，基于 Asia/Shanghai 自然日自动签到 +5 经验
- 手动签到：下拉菜单"签到"按钮兜底，已签到显示"今日已签到"并禁用
- 首次任务经验：上传头像/设置用户名/设置个性签名各 +10，审核通过与直接更新均触发
- 经验值变动后自动比对等级，升级时通过通知系统发送"恭喜提升至 LvX"
- 下拉菜单重构：顶部头像+用户名+LvX 等级标签，菜单项增加左侧图标，优化布局样式
- 新增 API：POST /api/level/checkin、GET /api/level/info

internal/controller/interfaces.go

@@ -61,3 +61,10 @@ type sessionManager interface {
 	DestroyOtherByUID(uid uint, currentSID string) error
 	UpdateRemark(sid string, uid uint, remark string) error
 }
+
+// levelUseCase LevelController 对 LevelService 的最小依赖
+type levelUseCase interface {
+	CheckIn(userID uint) (checkedIn bool, newExp int, levelUp bool, err error)
+	GetLevel(userID uint) (level int, exp int, checkedIn bool, err error)
+	CompleteTask(userID uint, taskType string) (newExp int, levelUp bool, err error)
+}

internal/controller/level_controller.go

@@ -0,0 +1,61 @@
+package controller
+
+import (
+	"net/http"
+
+	"metazone.cc/metalab/internal/common"
+
+	"github.com/gin-gonic/gin"
+)
+
+// LevelController 积分/等级/签到 API
+type LevelController struct {
+	levelSvc levelUseCase
+}
+
+// NewLevelController 构造函数
+func NewLevelController(levelSvc levelUseCase) *LevelController {
+	return &LevelController{levelSvc: levelSvc}
+}
+
+// CheckIn 手动签到 API
+func (lc *LevelController) CheckIn(c *gin.Context) {
+	uidVal, exists := c.Get("uid")
+	if !exists {
+		common.Error(c, http.StatusUnauthorized, "请先登录")
+		return
+	}
+	uid := uidVal.(uint)
+
+	checkedIn, newExp, levelUp, err := lc.levelSvc.CheckIn(uid)
+	if err != nil {
+		common.Error(c, http.StatusInternalServerError, "签到失败")
+		return
+	}
+
+	level, _, _, _ := lc.levelSvc.GetLevel(uid)
+	common.Ok(c, gin.H{
+		"checked_in": checkedIn,
+		"exp":        newExp,
+		"level":      level,
+		"level_up":   levelUp,
+	})
+}
+
+// GetLevel 获取当前等级、经验值和签到状态 API
+func (lc *LevelController) GetLevel(c *gin.Context) {
+	uidVal, exists := c.Get("uid")
+	if !exists {
+		common.Error(c, http.StatusUnauthorized, "请先登录")
+		return
+	}
+	uid := uidVal.(uint)
+
+	level, exp, checkedIn, err := lc.levelSvc.GetLevel(uid)
+	if err != nil {
+		common.Error(c, http.StatusInternalServerError, "获取失败")
+		return
+	}
+
+	common.Ok(c, gin.H{"level": level, "exp": exp, "checked_in": checkedIn})
+}

internal/controller/settings_api_profile.go

@@ -57,6 +57,14 @@ func (sc *SettingsController) UpdateProfile(c *gin.Context) {
 		return
 	}
 
+	// 触发首次任务奖励（静默失败不影响主流程）
+	if req.Username != "" {
+		_, _, _ = sc.levelSvc.CompleteTask(userID, "username")
+	}
+	if req.Bio != "" {
+		_, _, _ = sc.levelSvc.CompleteTask(userID, "bio")
+	}
+
 	common.OkMessage(c, "个人资料已更新")
 }
 
@@ -112,5 +120,8 @@ func (sc *SettingsController) UploadAvatar(c *gin.Context) {
 		return
 	}
 
+	// 触发首次上传头像奖励
+	_, _, _ = sc.levelSvc.CompleteTask(userID, "avatar")
+
 	common.Ok(c, gin.H{"url": url})
 }

internal/controller/settings_controller.go

@@ -40,6 +40,11 @@ type sessionConfig interface {
 	GetRememberTimeout() int // 分钟
 }
 
+// taskCompleter 设置页对等级服务的依赖（用于首次任务奖励）
+type taskCompleter interface {
+	CompleteTask(userID uint, taskType string) (newExp int, levelUp bool, err error)
+}
+
 // SettingsController 个人设置控制器
 type SettingsController struct {
 	authService   profileProvider
@@ -47,11 +52,12 @@ type SettingsController struct {
 	auditService  auditSubmittable
 	sessionMgr    sessionManager
 	sessionCfg    sessionConfig
+	levelSvc      taskCompleter
 }
 
 // NewSettingsController 构造函数
-func NewSettingsController(authService profileProvider, avatarService avatarProvider, auditService auditSubmittable, sessionMgr sessionManager, sessionCfg sessionConfig) *SettingsController {
-	return &SettingsController{authService: authService, avatarService: avatarService, auditService: auditService, sessionMgr: sessionMgr, sessionCfg: sessionCfg}
+func NewSettingsController(authService profileProvider, avatarService avatarProvider, auditService auditSubmittable, sessionMgr sessionManager, sessionCfg sessionConfig, levelSvc taskCompleter) *SettingsController {
+	return &SettingsController{authService: authService, avatarService: avatarService, auditService: auditService, sessionMgr: sessionMgr, sessionCfg: sessionCfg, levelSvc: levelSvc}
 }
 
 // SettingsPage 个人设置页面（需登录）