Add CLAUDE.md for AI-assisted development sessions

Author: DanEscher98

CLAUDE.md

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+# React Native Template - Claude Code Instructions
+
+## Project Overview
+This is a React Native + Expo SDK 54 template with TypeScript, NativeWind (Tailwind CSS), Drizzle ORM, and best practices for mobile development.
+
+## Tech Stack
+- **Framework**: React Native 0.81 + Expo SDK 54
+- **Language**: TypeScript (strict mode)
+- **Routing**: Expo Router (file-based routing in `src/app/`)
+- **Styling**: NativeWind (Tailwind CSS) - configure in `tailwind.config.js`
+- **Database**: Drizzle ORM with PostgreSQL - schemas in `src/db/schema/`
+- **Navigation**: React Navigation v7 (native stack + bottom tabs)
+- **Testing**: Jest + React Testing Library
+- **Architecture**: React Native New Architecture enabled (required for Worklets/Reanimated)
+
+## Development Workflow
+Use the **Justfile** for all development commands:
+
+```bash
+just dev          # Start Expo dev server
+just android      # Build and run on Android device/emulator
+just ios          # Build and run on iOS simulator
+just check        # Run lint, format check, typecheck, and tests
+just format       # Fix formatting issues
+just test         # Run tests
+just clean        # Clean build artifacts and caches
+```
+
+## Key Files
+- `src/app/` - Expo Router screens (file-based routing)
+- `src/components/` - Reusable components
+- `src/db/` - Drizzle ORM client and schemas
+- `src/services/` - API and external service integrations
+- `src/utils/` - Utility functions (including `cn()` for class merging)
+- `Justfile` - Development commands
+- `app.json` - Expo configuration
+
+## Styling with NativeWind
+Use Tailwind classes directly in components:
+```tsx
+<View className="flex-1 items-center justify-center bg-white">
+  <Text className="text-2xl font-bold text-gray-900">Hello</Text>
+</View>
+```
+
+Use `cn()` utility for conditional classes:
+```tsx
+import { cn } from '@/utils/cn';
+<View className={cn("p-4", isActive && "bg-blue-500")} />
+```
+
+## Database (Drizzle ORM)
+Define schemas in `src/db/schema/`:
+```typescript
+import { pgTable, serial, text, timestamp } from 'drizzle-orm/pg-core';
+
+export const items = pgTable('items', {
+  id: serial('id').primaryKey(),
+  name: text('name').notNull(),
+  createdAt: timestamp('created_at').defaultNow(),
+});
+```
+
+Run migrations with: `just migrate`
+
+## Testing with Waydroid (Linux)
+For testing on Linux without a physical device:
+1. Start Expo: `just dev`
+2. Set up ADB: `adb reverse tcp:8081 tcp:8081`
+3. Launch app: `adb shell am start -n com.template.app/.MainActivity`
+
+## EAS Build (Production)
+For production builds, see README.md for EAS setup instructions.
+
+## Important Notes
+- Always run `just check` before committing
+- The template uses Yarn Berry v4 with `node_modules` linker
+- New Architecture is enabled in `android/gradle.properties` (required for Worklets)
+- Keep dependencies updated to match Expo SDK version expectations