Why did Paul publicly oppose Peter in Galatians 2, and was Peter guilty of heresy or hypocrisy?

In Galatians 2:11–14, Paul recounts a moment when he publicly opposed Peter (Cephas) in Antioch. The issue appears to involve Peter's withdrawal from eating with Gentile believers when certain Jewish Christians arrived. Paul accuses Peter and others of hypocrisy and not acting "in step with the truth of the gospel." >"But when Cephas came to Antioch, I opposed him to his face, because he stood condemned..." (Gal. 2:11–14, ESV) Was Peter teaching or promoting heresy here, or was Paul's confrontation about inconsistent behavior rather than false doctrine? How have various Christian traditions historically interpreted this passage, especially regarding apostolic authority and church unity?