If Ting-Lu attacks with "Ground Crasher" against a 30 HP Cleffa with Bravery Charm attached while Jamming Tower is in play, would it do the damage first and KO Cleffa, or would Jamming Tower be discarded first and Cleffa survives due to its Bravery Charm reactivating?
The damage is indeed done first and then Jamming Tower is discarded, but lucky for Cleffa the check for KO does not happen until all damage and effects have been resolved. Cleffa would have 80HP and is not KO'd by Ground Crasher.
Source: TPCi Rules Team (2024-09-05)

Relevant cards

Note: All applicable cards may not be listed below.
SV6_110
SV6_110
SV2_173
SV2_173
SV6_153
SV6_153