Child Damage Mitigation

I would buy some dog/child gates/fences on Amazon.
They have a nice selection. I don't know how your room is laid out, but Amazon sells some nice folding fences that allow you to place them where needed and are easily moved when not wanted.
I use them for my dogs, and my system is safe from their little paws.
Bob

Another option may be a helmet for the kid.

By the way, your days of "sitting in the sweet spot enjoying my audiophile-grade recordings" have been numbered. Hopefully, you have a long commute to make up for that.

While you are at that, get it while you can. You may or may not be sorry, but she will appreciate it one day.

https://www.ebay.com/itm/Walt-Disney-The-Best-Of-Disney-Vinyl-Compilation-Album-1985-REH-573-VG/2239...

separate locked listening room.

When my wife decided she wanted a cat, I bought a couple plastic lenses designed to be used on a 4 ft. fluorescent light fixture.  They are translucent and pretty thin, maybe 1/32 inch, strong but very flexible.  When I'm not listening, I bend them around the front of my speakers and secure them with a bungee cord a half foot up from the floor.  They are easily removed for listening and fully protect the grills from the cat when the system is off.  Aesthetically pleasing?  Well, no.  Effective?  100%.
Otherwise, try the "velcro babysitter"...a square of velcro a couple square feet.  One side mounted about half way up the wall of your choice, the other sheet with a hole cut into it large enough to go over the baby's head and secured around the baby's torso.  When you're not in the room, you just velcro the tot to the wall.

Back in the day when Maggies came out the tri panel ones the dealer warp his knuckles on them and said that they we bullet proof.  Has that changed?