A 28-year-old man from Bangalore presents with a 3-year history of intense, irrational fear of dogs. He reports that whenever he encounters a dog, even from a distance, he experiences rapid heart rate, shortness of breath, and an overwhelming urge to escape. He has restructured his daily life to avoid parks, walking routes where dogs are common, and visiting friends who own pets. His anxiety is limited to dogs; he does not experience panic attacks in other situations. He recognizes that his fear is excessive but feels unable to control it. What is the most likely diagnosis?