feat: 公告系统 — Phase 2 完成

- Model/Repo/Service/Controller 全栈实现
- CRUD + ListActive（生效时间范围过滤）
- 管理后台独立页面 /admin/announcements（列表+弹窗CRUD）
- 前台首页 Hero 下方公告栏（info/success/warning/error 四色）
- Moderator+ 权限可管理公告

internal/router/admin.go

@@ -32,6 +32,7 @@ func setupAdminRoutes(r *gin.Engine, cfg *config.Config, d *dependencies) {
 		adminPages.GET("/energy/logs", d.adminEnergyCtrl.EnergyLogPage)
 		adminPages.GET("/energy/fund-logs", d.adminEnergyCtrl.FundLogPage)
 		adminPages.GET("/comments", d.adminCommentCtrl.CommentsPage)
+		adminPages.GET("/announcements", d.announcementCtrl.Page)
 	}
 
 	// --- 管理后台 API ---
@@ -99,4 +100,17 @@ func setupAdminRoutes(r *gin.Engine, cfg *config.Config, d *dependencies) {
 		adminCommentAPI.GET("", d.adminCommentCtrl.ListComments)
 		adminCommentAPI.DELETE("/:id", d.adminCommentCtrl.Delete)
 	}
+
+	// --- 公告管理 API（moderator+） ---
+	announcementAPI := r.Group("/api/admin/announcements")
+	announcementAPI.Use(d.authMdw.Required())
+	announcementAPI.Use(middleware.RequireMinRole(model.RoleModerator))
+	announcementAPI.Use(d.authMdw.BannedWriteGuard())
+	announcementAPI.Use(middleware.CSRF(cfg))
+	{
+		announcementAPI.GET("", d.announcementCtrl.List)
+		announcementAPI.POST("", d.announcementCtrl.Create)
+		announcementAPI.PUT("/:id", d.announcementCtrl.Update)
+		announcementAPI.DELETE("/:id", d.announcementCtrl.Delete)
+	}
 }