refactor: fix biome linting issues and update project documentation

- Fix 36+ biome linting issues reducing errors/warnings from 227 to 191
- Replace explicit 'any' types with proper TypeScript interfaces
- Fix React hooks dependencies and useCallback patterns
- Resolve unused variables and parameter assignment issues
- Improve accessibility with proper label associations
- Add comprehensive API documentation for admin and security features
- Update README.md with accurate PostgreSQL setup and current tech stack
- Create complete documentation for audit logging, CSP monitoring, and batch processing
- Fix outdated project information and missing developer workflows

lib/sendEmail.ts

@@ -47,7 +47,7 @@ export async function sendEmail(
       console.log("📧 [DEV] Email would be sent:", {
         to: options.to,
         subject: options.subject,
-        text: options.text?.substring(0, 100) + "...",
+        text: `${options.text?.substring(0, 100)}...`,
       });
       return { success: true };
     }