How to protect a 1A 120V circuit breaker from direct short?
If you did indeed damage your 1A breaker, then I suspect that you exceeded the maximum interrupting current specified by the manufacturer. For example, if you have a 120VAC circuit, and 10A of load brings it down to 118V, then you have 600 Amps of short circuit current so your interrupting current on the circuit protection device needs to be at least that big.

To answer the question other than telling you to get a better circuit breaker: put a resistor in series with your AC supply to reduce the short circuit current of your supply. It will have to very high wattage resistor. One or more large several hundred Watt light bulbs works great for a resistor.