refactor: pecah lib/api.ts dan constants/Styles.ts per domain

- lib/api.ts (879 baris) → 13 file di lib/api/ per domain
- constants/Styles.ts (1.275 baris) → 10 file di constants/styles/ per domain
- tambah docs/FILE-HEALTH.md dan referensinya ke CLAUDE.md
- kedua file lama tetap sebagai re-export — zero breaking changes

constants/styles/index.ts

@@ -0,0 +1,26 @@
+import { StyleSheet } from "react-native";
+import SpacingStyles from './spacing.styles';
+import TypographyStyles from './typography.styles';
+import LayoutStyles from './layout.styles';
+import BorderStyles from './border.styles';
+import ButtonStyles from './button.styles';
+import InputStyles from './input.styles';
+import CardStyles from './card.styles';
+import ModalStyles from './modal.styles';
+import HeaderStyles from './header.styles';
+import ComponentStyles from './component.styles';
+
+const Styles = StyleSheet.create({
+   ...SpacingStyles,
+   ...TypographyStyles,
+   ...LayoutStyles,
+   ...BorderStyles,
+   ...ButtonStyles,
+   ...InputStyles,
+   ...CardStyles,
+   ...ModalStyles,
+   ...HeaderStyles,
+   ...ComponentStyles,
+});
+
+export default Styles;