AI SEO stack upgraded to v5.0 (based on AI SEO 2026+ v9.0)

Added W3C Agent Protocol (agent.json), WebMCP Tools (webmcp.json), NLWeb Schema Aggregation (schemamap.json), IAB CoMP v1.0 (comp.json), audit trail endpoint, knowledge graph endpoint, and JSON feed. Google Analytics G-2EWNGXF546 hardcoded as fallback. Fixed nginx UTF-8 encoding.