You're asking 3 questions.
How can you fly at 0kts without stalling?
Have a thrust:weight ratio greater than one. John Klatt's Screaming Sasquatch is one such airplane.
In practice, can a maneuver be performed that, by bringing the aircraft to, or very close to 0g, also brings the aircraft to a temporary standstill, or near standstill, in terms of true air speed?
Sure. Pull to vertical (or near vertical) and wait. You'll hit zero airspeed right before gravity reasserts itself. As Carlo Felicione mentioned in his answer, a hammerhead maneuver will do this. There are other maneuvers as well. The main idea is to convert your forward momentum into a vertical climb and stop depending on the wings for lift.
When I perform a loop (I fly an aerobatic plane -- DON'T try this in a Cessna!) the aircraft is essentially ballistic across the top of the loop. It will indicate 0 knots airspeed regularly (that's the trick to making round loops)
Can such a maneuver be performed without exceeding 30° pitch?
Probably not, and the fact that you're asking is kind of scary.
Probably not because you won't have enough upward momentum to offset gravity between the time your wings stop producing lift and when you hit zero airspeed.
Scary because these are aerobatic maneuvers, and attempting them in the wrong aircraft without training is stupid dangerous.