A 52-year-old male farmer from rural Maharashtra presents with a 5-day history of right eye pain, photophobia, and purulent discharge. He reports a thorn prick injury to the cornea while working in the field 2 weeks ago. On examination, visual acuity is 6/60, corneal sensation is reduced, and there is a 4 mm central corneal ulcer with raised edges, stromal infiltration, and a hypopyon. Gram stain of corneal scrapings shows gram-positive cocci in clusters. Culture on blood agar shows golden-yellow colonies. What is the most likely causative organism?