You are correct, you can’t make new contributions to an HSA unless you are covered by a qualifying HDHP and no “other” coverage. The HRA counts as other coverage and disqualifies you from contributing to an HSA.
I believe the HRA must be renewed each year. Any unspent funds in the HRA may roll over to the next year or may be returned to the employer but can not be distributed to you for any reason except reimbursement of qualified medical costs. If you declined to participate in the next plan year—and you are still covered by a qualifying HDHP—you could resume HSA contributions.
