Why’s my new outlet tripping the switch in the panel?

TL;DR Remove the tab on the hot (red/black) side

"A/B" plus the symptoms sounds like you have a Multi Wire Branch Circuit or MWBC. With an MWBC, you can have the top receptacle's hot on one part of the circuit and the bottom receptacle's hot on the other part of the circuit. Each receptacle is then 120V hot-to-neutral but the two hots are 240V apart. With the tab removed on the hot (red/black) side, the two circuits are separate on hot but share neutral. With the tab in place (factory default), you have a short circuit between the two hots - 240V at maximum possible current, which quickly (and correctly) trips the breaker.

Remove the tab, only on the hot side, and everything should work.

While you're at it, check the "A/B". There should be a common shutoff - i.e., either they are part of a double-breaker or have a "handle tie" between the two parts. If you are not sure, upload a picture of the breaker panel.

GFCI

Because this is in the kitchen, it should be (must be on many new installations, depending on location) GFCI-protected. With non-MWBC circuits, this can be done at the receptacle or breaker. With MWBC, this can be done (practically speaking) only at the breaker. If your breaker has a "TEST" button, then you are probably fine. If not, upload a picture to get some advice.