I would like to know how to connect GPIO to LinuxCNC’s E-Stop chain.

Come here first.

Too many times users have received info from chatgpt that make absolutely no sense.

Google searching for "linuxcnc estop latch" gives the link above as the 4th result.
Or you could use the search function of the forum.

Ahh, no discernible action when I hit SUBMIT the first time. I can wait it out in the future.

If I use the following code which has the one missing dash error that I corrected:

# estop
loadrt estop_latch
addf estop-latch.0 servo-thread
net estop-loopout iocontrol.0.emc-enable-in <= estop-latch.0.ok-out
net estop-loopin iocontrol.0.user-enable-out => estop-latch.0.ok-in
net estop-reset iocontrol.0.user-request-enable => estop-latch.0.reset
net remote-estop estop-latch.0.fault-in <= parport.0.pin-in-10-not

The bug-a-boo for me is how do I tie the GPIO25 to the remote-estop. Do I change the last line to:
net remote-estop estop-latch.0.fault-in <= hal_gpio.GPIO25-in-10-not

?

Depends on what the machine has for an e-stop chain and that is wired, but for small machines that can not do much harm, a simple and single input and a single output are all that is needed:
# --- ESTOP-EXT ---
net estop-ext <= [HMOT](CARD0).7i84.0.2.input-14
net estop-ext => [HMOT](CARD0).7i84.1.1.output-08
That will just loop back the e-stop signal from the button to whatever is connected to the output pin. This works perfectly well on most machines (example is from my 3.5 ton Mazak lathe) as the output is wired to existing e-stop loop on the machine.
That will not allow the machine to come on when the button is pressed and will allow enabling the machine when button is reset.
E-stop latch should be used only when more logic is required by LinuxCNC, and/or more inputs and outputs.

Personally I would have the estop connected via Normally closed switch, and the estop is signaled via opening connection. This way if, for whatever reason, the estop wire is broken or falls off either connection the machine will go into an estop condition.
The way you have your schematic, you'll only know that something is wrong with the estop when you go to use it.
I'd rather a failing estop not let the machine run.

Part of failing is what you learn along the way. I know of "a rule" that eStops should be Normally Closed. Yesterday, that is all I knew. Today however, I am well-versed in ISO 13850:2015 Safety of Machinery - Emergency stop functions - Principles for design. Today I have a strong opinion that you are right! The reality is my schematic I'm using from Byte2Bot does it otherwise, so shall I.
But we divert! I don't see any GPIO25's in this banter.