fix: handle large terminated sessions caching with pagination to prevent RAM overflow;

feat: add paginated query for terminated sessions GUIDs with limit and offset;
refactor: batch processing terminated sessions in Redis with pipeline;
chore: log batch caching progress for terminated sessions;
fix: set TTL for session termination cache keys (8 hours);
refactor: update SQL query for terminated sessions to use pagination;
fix: correct loop structure in auth service initialization

backend/internal/database/query.sql.go

@@ -508,15 +508,22 @@ func (q *Queries) GetSessionByGuid(ctx context.Context, guid string) (Session, e
 	return i, err
 }
 
-const getUnexpiredTerminatedSessionsGuids = `-- name: GetUnexpiredTerminatedSessionsGuids :many
+const getUnexpiredTerminatedSessionsGuidsPaginated = `-- name: GetUnexpiredTerminatedSessionsGuidsPaginated :many
 SELECT guid FROM sessions
 WHERE 
   terminated IS TRUE AND
   last_refresh_exp_time > CURRENT_TIMESTAMP
+LIMIT $1::integer
+OFFSET $2
 `
 
-func (q *Queries) GetUnexpiredTerminatedSessionsGuids(ctx context.Context) ([]pgtype.UUID, error) {
-	rows, err := q.db.Query(ctx, getUnexpiredTerminatedSessionsGuids)
+type GetUnexpiredTerminatedSessionsGuidsPaginatedParams struct {
+	BatchSize int32
+	Offset    int64
+}
+
+func (q *Queries) GetUnexpiredTerminatedSessionsGuidsPaginated(ctx context.Context, arg GetUnexpiredTerminatedSessionsGuidsPaginatedParams) ([]pgtype.UUID, error) {
+	rows, err := q.db.Query(ctx, getUnexpiredTerminatedSessionsGuidsPaginated, arg.BatchSize, arg.Offset)
 	if err != nil {
 		return nil, err
 	}