feat: impl refresh token rotation

apps/backend/internal/auth/grant.go

@@ -0,0 +1,22 @@
+package auth
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/uptrace/bun"
+)
+
+type Grant struct {
+	bun.BaseModel `bun:"grants"`
+
+	ID        uuid.UUID  `bun:",pk,type:uuid"`
+	UserID    uuid.UUID  `bun:"user_id,notnull"`
+	CreatedAt time.Time  `bun:"created_at,notnull,nullzero"`
+	UpdatedAt time.Time  `bun:"updated_at,notnull,nullzero"`
+	RevokedAt *time.Time `bun:"revoked_at,nullzero"`
+}
+
+func newGrantID() (uuid.UUID, error) {
+	return uuid.NewV7()
+}