PHILADELPHIA — Vice President Kamala Harris’ strong debate performance has sent her campaign surging into the final weeks of the race with newfound confidence, sharper ideas about how to convince the country that former President Donald Trump is unfit for office, and a host of questions about what comes next. The Tuesday clash had long stood out as the final tent-pole moment for Harris on the campaign calendar, with the vice-presidential candidates set to face off Oct. 1. Now, her team is fully open to a second debate with Trump, though he appears noncommittal. While Harris’ top aides are thrilled with her debate showing and Trump’s inability to push consistent and coherent attacks, they are looking to tweak their strategy only around the edges. As new details emerge about the 34-year-old man from Riverside County accused of starting the now 36,500-acre Line Fire, as well as how he came to the attention of authorities. Halstenberg, who lives in Norco, nearly 50 miles away from where the Line Fire started, was arrested on Sept. 9 for arson. Investigators said they were able to use license plate readers and other means that put the 34-year-old in the vicinity of where the fire started in Highland on Sept. 5 and added that they have surveillance footage among other evidence collected during the investigation.