File Refactor

Keep every source file under 500 lines. Split before it crosses the limit.

When to trigger

• A file exceeds 500 lines
• A module mixes types, utils, handlers, rendering, and constants
• A screen component contains inline sub-components that are extractable
• A service combines pure helpers, dataclasses, and orchestration in one file

TypeScript / React splitting order

1. Types — interfaces, type aliases, enums → types.ts
2. Pure utilities — formatting, grouping, transforms → utils.ts
3. Complex state logic → hooks/useXxx.ts
4. Sub-components — UI pieces → components/XxxYyy.tsx
5. Constants / config — hardcoded arrays, config objects → constants.ts