As the old saying goes, the truth is always stranger than fiction, and indeed there are some true stories so strange that they can’t be fully expressed with familiar modes of storytelling. Such is the case of “Rogue Agent,” a film that unfolds as a spy thriller and romantic drama before it takes a hard left into the seamy world of scam artistry. For British viewers, the sordid story of Robert Freegard is likely well-known. The tale will even feel familiar for American viewers, thanks to the Netflix true crime series “The Puppet Master: Hunting the Ultimate Conman.” But the two projects take co…