Butt your enclosure right up against the lock body, then you reduce shearing forces trying to pull it off the door. Extend the pull bar through your enclosure so you still have a manual override.
While I'm not adverse to home automation, is this something you need in your life, or just want? I like my perimeter security too be simple and tight, extra complications make the security audit much harder.
Will your insurance stand up to home made remote control unlocking?
To answer your question, place the servo in a suitably large enclosure and practically any adhesive should work, e.g. 3mM command strips or even velcro or double sided sticky. When confident that this is what you want, use a screw.
Arduino and esp32 are both good places to start. On YouTube look up ralph s bacon I think he is - He does lots of microcontroller stuff, and of course the likes of big clive will teach you all about basic electronic circuits.
If you're a complete newbie, get a kit and work through the tutorials.
Stuff you'll need at first is a microcontroller, prototyping breadboard and a few components (should all come in the kit of you go that route). When you have something that works that you want to keep, you can think about a cheap (ish) soldering station and either veroboard, or look into getting your own boards made.
A multimeter will help a lot (cheapish will do) and depending on how deep you get, a bench power supply and an oscilloscope, but you can live without those for a while.
Get good quality solder, and using extra food quality flux changed the game for me. If you are an older person, magnification really helps too!
Get components in 10's or more as you'll save a little and it doesn't matter much if you let out the magic smoke. For hobby stuff, Alix is your friend.
Have fun.
Brilliant, many thanks. With all the old phones in my cupboards I'd hoped this was the answer, but it's good to get a second opinion.