The Port of Oakland has been brought to a grinding halt this week as hundreds of protesting truckers hold a key commerce hub captive. The action — following a similar one at Southern California ports last week — has dealt another blow to supply chains already reeling from pandemic delays. The self-employed truckers are calling on Gov. Gavin Newsom to amend AB 5, a controversial labor law that could end their business model. Some say they will continue the port shutdown until they get action. But it is unclear what, if anything, the governor could or will do to end the blockade at one of the We…