Implement account management features in API, including endpoints for listing accounts and updating account roles. Introduce moderator role with associated permissions, and refactor access control checks to accommodate staff roles. Update database schema to support new role constraints and enhance frontend navigation for staff access.

backend/internal/domain/model.go

@@ -22,8 +22,9 @@ type ID string
 type GlobalRole string
 
 const (
-	RolePlayer GlobalRole = "player"
-	RoleAdmin  GlobalRole = "admin"
+	RolePlayer    GlobalRole = "player"
+	RoleModerator GlobalRole = "moderator"
+	RoleAdmin     GlobalRole = "admin"
 )
 
 type Account struct {
@@ -36,6 +37,7 @@ type Account struct {
 }
 
 func (a Account) IsAdmin() bool { return a.Role == RoleAdmin }
+func (a Account) IsStaff() bool { return a.Role == RoleAdmin || a.Role == RoleModerator }
 
 type Ratings struct {
 	Tank    int `json:"tank"`