A 33-year-old male presents with a 2-year history of excessive daytime sleepiness despite reporting 8-9 hours of sleep per night. He describes irresistible urges to nap during the day, often falling asleep during meetings at work. He reports episodes where he suddenly feels weak in the knees and his jaw goes slack during moments of strong emotion such as laughing or surprise, lasting seconds to a minute. He occasionally experiences vivid, dream-like hallucinations as he is falling asleep and reports episodes of being unable to move for 1-2 minutes upon waking. His BMI is 23, he does not snore, and his bed partner confirms no observed apneic episodes. Epworth Sleepiness Scale score is 18. He has no psychiatric history and denies substance use. What is the MOST likely diagnosis?