Get diagnostics for file and/or project.
- Provide file path to get diagnostics for that file - Leave path empty to get diagnostics for entire project - Results displayed in structured format with severity levels - Displays errors, warnings, and hints - Groups diagnostics by severity - Provides detailed information about each diagnostic - Results limited to diagnostics provided by LSP clients - May not cover all possible code issues - Does not provide suggestions for fixing issues - Use with other tools for comprehensive code review - Combine with LSP client for real-time diagnostics