Consider: Add the 2026 opcodes early

While there's is still some time left until the formal lock-in, we might want to go ahead and do the work to add the 2026 opcodes early, then temporarily mark them as expected to activate in May 2026.

It's a bit premature, but they seem well supported already and there's some benefits to having them in early, particulary with regards to the BCH Blaze hackathon.