That shower system is called "junk" lol. What a horrible idea.

hinge on left is a "face frame cup hinge"- other names exist hinge on right is "euro hinge" other names exist In both cases there are at least 6 mfgs who have up to dozens of variations of swing, cabinet clip, attachment... What do you really need to know? Soft close hinges- newest and most common the soft close is built into the hinge. Older ones had a piston mounted in the cabinet for the door to hit on closing. You might be able to clean them- carefully- no solvents, no WD40 (which is a solvent) but unlikely. On newer glides the soft close mechanisms is integral and can't really be repaired. The older (over 5 years) could be replaced if they were blum. Note that dust can be the death of undermount glides. Sawdust from install not cleaned or worse, granite dust and often the glides will have to be replaced. Keep after your installers.

You have a lovely view and I think your idea of panels sounds great if you want to leave all that wonderful light. I'm Nana to two little ones and had two daughters--so I've seen this suggestion actually work---at least for food. We had the rule that you only eat sitting down at the table, bar, or highchair. Then hands were cleaned immediately after eating before they're allowed to wander through the house. So--no food gets on curtains. Now, :~) that doesn't take care of teething slobbery fingers on them or the windows, but it does cut down on the big stuff. And when they're helping you "cook", keep a damp cloth beside you so that when they've sampled and get down, you can wipe before they wander. Good luck and enjoy your inviting home!

Those are business security doors (or gates).... Installed per manufacture directions Rail at the top and the Sides, I suppose. Don't think these types of doors are "inviting", they are more to protect the content where they can not be hooked to a truck, and designed not to be kicked in. >This door is very popular in my country. Sorry.