auto-claude: subtask-1-2 - Document code style conventions and linting

CONTRIBUTING.md

@@ -217,6 +217,69 @@ Ensure the build completes without errors before submitting.
 
 ## Code Style & Standards
 
+### ESLint & Code Linting
+
+This project uses ESLint to enforce code quality and consistency. The configuration extends Next.js recommended presets:
+
+**ESLint Configuration** (`.eslintrc.json`):
+```json
+{
+  "extends": [
+    "next/core-web-vitals",
+    "next/typescript"
+  ]
+}
+```
+
+**Key ESLint Rules:**
+- `next/core-web-vitals` - Enforces Next.js best practices and Core Web Vitals optimizations
+- `next/typescript` - TypeScript-specific rules for Next.js applications
+
+**Running the Linter:**
+```bash
+# Run ESLint in strict mode (recommended before committing)
+npm run lint
+
+# The linter will check for:
+# - Code quality issues
+# - Next.js best practices violations
+# - TypeScript type errors
+# - Unused variables and imports
+# - Accessibility issues
+```
+
+**Important:**
+- Always run `npm run lint` before committing changes
+- Fix all linting errors - the project uses `--strict` mode
+- The linter runs automatically during the build process
+- ESLint errors will prevent successful production builds
+
+### Code Formatting
+
+**General Formatting Guidelines:**
+- **Indentation:** 2 spaces (no tabs)
+- **Line Length:** Aim for 80-100 characters, hard limit at 120
+- **Semicolons:** Required at the end of statements
+- **Quotes:** Single quotes for strings (except in JSX/TSX where double quotes are preferred)
+- **Trailing Commas:** Use trailing commas in multi-line objects and arrays
+
+**Example:**
+```typescript
+// ✅ Good
+const user = {
+  name: 'John Doe',
+  email: 'john@example.com',
+  role: 'admin',
+};
+
+// ❌ Bad
+const user = {
+  name: "John Doe",
+  email: "john@example.com",
+  role: "admin"
+}
+```
+
 ### TypeScript
 - Use TypeScript for all new files
 - Define proper types and interfaces