docs: add contributing guide and CLAUDE.md (#32)

* docs: add contributing guide and CLAUDE.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* chore: add changeset

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* docs: improve command descriptions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: VdustR

.changeset/docs-contributing.md

@@ -0,0 +1,5 @@
+---
+"@vp-tw/eslint-config": patch
+---
+
+Add contributing guide and CLAUDE.md

CLAUDE.md

@@ -0,0 +1,95 @@
+# ESLint Config Development Guide
+
+## Architecture
+
+```
+packages/eslint-config/src/
+├── vdustr.ts          # Main entry point, orchestrates all configs
+├── configs/           # Optional feature configs (emotion, mdx, prettier, etc.)
+├── extends/           # Extensions for antfu configs (react, yaml, etc.)
+├── lib/               # Dynamic import wrappers for optional dependencies
+├── utils/             # Shared utilities (mergeConfig, extendsConfig, etc.)
+└── types.ts           # Type definitions
+```
+
+## Key Patterns
+
+### Dynamic Imports for Optional Dependencies
+
+Optional ESLint plugins must use dynamic imports to avoid loading when disabled:
+
+```typescript
+// src/lib/eslint-react.ts
+import type EslintReact from "@eslint-react/eslint-plugin";
+import { interopDefault } from "@antfu/eslint-config";
+
+// IMPORTANT: Explicit return type required to avoid TS2742 build errors
+const eslintReact = (): Promise<typeof EslintReact> =>
+  interopDefault(import("@eslint-react/eslint-plugin"));
+
+export { eslintReact };
+```
+
+**Why explicit types?** Without them, TypeScript cannot infer types referencing internal modules (e.g., `@eslint-react/shared`), causing TS2742 errors during `unbuild`.
+
+### extendsConfig Pattern
+
+Use `extendsConfig` to extend antfu's configs conditionally:
+
+```typescript
+extendsConfig(composer, "antfu/react/rules", async (config) => {
+  // Only executes if "antfu/react/rules" exists
+  const plugin = await importPlugin();
+  return [config, modifiedConfig];
+});
+```
+
+### Config Structure
+
+- `configs/` - Standalone configs that use `config.append()`, return arrays
+- `extends/` - Modify existing antfu configs via `extendsConfig()`
+- `lib/` - Dynamic import wrappers, always require explicit return types
+
+## Commands
+
+```bash
+pnpm build              # Build @vp-tw/eslint-config (in packages/eslint-config)
+pnpm test               # Run tests for @vp-tw/eslint-config
+pnpm run checkTypes     # Type check entire workspace (root)
+pnpm lint               # Lint entire workspace (root)
+```
+
+## Release
+
+Managed by changesets. CI auto-publishes on main branch merge.
+
+```bash
+pnpm changeset          # Create changeset (interactive)
+# Or manually create .changeset/<name>.md
+```
+
+## Common Issues
+
+### TS2742: Inferred type cannot be named
+
+**Cause:** Dynamic import returns type referencing internal module.
+**Fix:** Add explicit return type annotation.
+
+```typescript
+// Bad - causes TS2742
+const fn = () => interopDefault(import("pkg"));
+
+// Good
+const fn = (): Promise<(typeof import("pkg"))["default"]> => interopDefault(import("pkg"));
+```
+
+### Feature not loading when enabled
+
+Check `vdustr.ts` for conditional logic. Features disabled by default need explicit enable check:
+
+```typescript
+const reactEnabled = Boolean(antfuOptions?.react ?? false);
+if (reactEnabled) {
+  react(config, vpOptions?.extends?.react);
+}
+```

README.md

@@ -85,16 +85,43 @@ export default vdustr({
 
 Automatically sorts keys in `pnpm-workspace.yaml` alphabetically using `yaml/sort-keys` rule.
 
-## Release
+## Contributing
+
+### Development
+
+```bash
+pnpm install            # Install dependencies
+pnpm build              # Build @vp-tw/eslint-config (in packages/eslint-config)
+pnpm test               # Run tests for @vp-tw/eslint-config
+pnpm run checkTypes     # Type check entire workspace
+pnpm lint               # Lint entire workspace
+```
+
+### Release
+
+Managed by [changesets](https://github.com/changesets/changesets). CI auto-publishes when merged to main.
 
 ```bash
-pnpm -w v:patch # or
-pnpm -w v:minor # or
-pnpm -w v:major
+pnpm changeset          # Create changeset interactively
+```
+
+### Adding Dynamic Import Wrappers
+
+When adding support for optional ESLint plugins, create a wrapper in `src/lib/`:
 
-pnpm -r publish
+```typescript
+// src/lib/my-plugin.ts
+import type MyPlugin from "eslint-plugin-my";
+import { interopDefault } from "@antfu/eslint-config";
+
+// Explicit return type required to avoid TS2742 build errors
+const myPlugin = (): Promise<typeof MyPlugin> => interopDefault(import("eslint-plugin-my"));
+
+export { myPlugin };
 ```
 
+See [CLAUDE.md](./CLAUDE.md) for detailed architecture and patterns.
+
 ## License
 
 MIT © ViPro <vdustr@gmail.com> (<http://vdustr.dev>)