Catchment system for leaks at plumbing joints?

You need to go back to Plumbing 1-01. There should be no reason to expect a leak.

They do make alarm systems for water leaks, they aren't cheap. Also, there are pressure sensitive supply lines that shut off if a rupture happens. If everything is installed correctly, there should be near zero expectation of a leak. If you don't trust your plumbing skills, pressurize the water system with air and a dial pressure indicator. Typical inspection done this way is 24 hr test.