lightning network – How to encode for LND `/v2/signer/verifymessage`?

Talking to just one node (baby steps), I want to call /v2/signer/verifymessage giving the output of lncli signmessage "Hello, Jessica". On the alice node on Polar, I get:

d9aa91ggo54ouho9axcw3itokb5u697tigi1r8o1kq4qkx87acduoz5f5wnxyts8dt8emhie9r3gnkxkwo5ogzo5xwsrfkhzpg5qnnmh

How do I encode this to send over to /v2/signer/verifymessage? I’m only slightly familiar with low-level string manipulation. The api says to send bytes, but what format (hoping this question makes sense)?

If it helps, I’m comfortable with Ruby, but I can probably figure it out if I see examples in JS or Python.