WASHINGTON — Hunter Biden offered Tuesday to testify publicly before Congress, striking a defiant note in response toa subpoena from Republicansand setting up a potential high-stakes face-off even as a separate special counsel probe unfolds and his father, President Joe Biden, campaigns for reelection. The Democratic president’s son slammed the subpoena’s request for closed-door testimony, saying it could be manipulated.... James Comer of Kentucky, the chairman of the House Oversight Committee,