How do you build doors like this one? Frame and panel, M&T joinery, inside
edge is chamfered.

https://tinyurl.com/ChamferDoor

Full link:

https://www.homecrestcabinetry.com/-...or_natural.jpg

Does the chamfer extend all the way to the ends of the stiles with a
matching "inside chamfer" (?) on the ends of the rails to create the
crisp corner?

This guys cleans up the corners after routing the assembled frame, but I
can't see (me) doing that for the 120+ corners I'd need to clean up for my
kitchen doors and drawers.

http://www.wooditis.com/attention-to-detail/

I'm sure hoping that there is some router table/table saw trick that
I don't know about.