Get the full profile of one healthcare vendor by slug. Use this after match_practice or search_providers when the user asks to "tell me more about [vendor]", "what services does [vendor] offer", "where did GPH get this information", or wants contact info or services for a specific provider. Returns company_name, category, city/state, quality_score (0-100; profile completeness, not a quality rating; 0 means never scored), description, services offered, practice_size_fit, phone and website where listed, Google rating and Google review count where present, a Provenance section that labels each fact GPH-researched, Vendor-supplied, GPH-verified or GPH conclusion with its last-checked date where one exists, and the profile URL. No listing carries a verified badge: the legacy verified flag is not a recorded check and is not shown. Where a vendor has been enrichment-extracted, the description, services and practice-size fit come from that extraction, the profile adds certifications and compliance attestations, locations served and founding year where extracted, and the response states the extraction confidence and what it was grounded in (where the extraction abstained on practice-size fit, the legacy listing value is returned and labelled as not extracted); otherwise the legacy listing fields are returned. Slug comes from match_practice or search_providers results; returns an error if the slug is unknown.