Structure for future agents and developers

See AGENTS.md for the codebase guide. The immutable reducer is in src/lib/chat-state.ts; orchestration is in src/hooks/useMessenger.ts. Provider and stream-framing code are separate from rendering. src/components/ contains the composer, emoji picker, poll composer/card, message actions, media viewer, and presence indicator. English/Arabic strings live in src/lib/i18n.ts.