Perform comprehensive code quality and security checks

# Check

Perform comprehensive code quality and security checks.

## Primary Task:
Run `npm run check` (or project-specific check command) and resolve any resulting errors.

## Important:
- DO NOT commit any code during this process
- DO NOT change version numbers
- Focus only on fixing issues identified by checks

## Common Checks Include:
1. **Linting**: Code style and syntax errors
2. **Type Checking**: TypeScript/Flow type errors
3. **Unit Tests**: Failing test cases
4. **Security Scan**: Vulnerability detection
5. **Code Formatting**: Style consistency
6. **Build Verification**: Compilation errors

## Process:
1. Run the check command
2. Analyze output for errors and warnings
3. Fix issues in priority order:
   - Build-breaking errors first