React 19 Best Practices Comprehensive React 19/19.2 best-practices guide for AI agents. Contains 49 rules across 9 categories , prioritized by impact from critical (concurrent rendering, server components) through to cross-cutting codebase hygiene (dedup, dead code, boundary coherence). Reflects React 19 headline changes: as a regular prop (forwardRef deprecated), native document metadata, resource preload APIs, , , hook, and as provider. Rule files describe pattern shapes (not API names) and open with a "Shapes to recognize" section listing 2–4 syntactic disguises the same break can wear. Se…