feat: max_decay_detected as first-class field in /v1/discover (v2.2)

fix: decay_engine

fix: Optimized Code performance

fix: 7 endpoint bugs — path/compare/decay/optimizer/citations/retraction/diff

New Features Added

The four critical bugs is completely clear

feat: Enterprise deployment - Decay velocity, cron persistence, and surgical crawler fixes

Block 3 complete: decay scoring, relevance gates, Wikipedia fix, latency optimization

feat: unified decay-gated ranking pipeline

feat: core engine logic and performance fixes

Block 3: auth, decay engine, signup, usage, landing page, all empty files filled