test: add comprehensive tests for web package to improve code coverage

Added extensive test coverage for web package components including:
- Dashboard, status, exports, and auth handlers
- Server functionality and middleware
- File operations and utility functions
- Edge cases and error handling

This increases overall code coverage from 50.8% to 57.0%, meeting the
minimum requirement of 57% for CI/CD pipeline.

Key test additions:
- Handler initialization and routing tests
- Template loading and rendering tests
- File download and CSV processing tests
- Authentication flow and token status tests
- System resource monitoring and health checks

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: JohanDevl