Add GraphQL lint with a number of (configurable) rules.

[ddebrunner]

Add GraphQL Linting with Custom Rules and Configuration

Summary

Implements a comprehensive GraphQL linting system for the StepZen VS Code extension with configurable rules and real-time feedback.

Features

• 5 custom linting rules: no anonymous operations, no duplicate fields, require descriptions, require deprecation reasons, field naming conventions, and root field nullability
• Configurable rule system: Enable/disable individual rules via VS Code settings
• Dynamic updates: Rule changes take effect immediately without extension restart
• VS Code integration: Linting errors/warnings appear in Problems panel with precise line/column locations
• Auto-linting: Optional automatic linting on file save
• Command integration: "StepZen: Lint GraphQL Schema" command for manual linting

Technical Details

• Uses GraphQL parser for accurate AST-based linting
• Modular rule system for easy extension
• Configuration-driven rule activation
• Proper VS Code diagnostic collection integration
• File watching with debounced auto-linting

Files Changed

• src/services/graphqlLinter.ts - Core linting service with custom rules
• src/commands/lintGraphQL.ts - Manual linting command
• src/commands/configureLintRules.ts - Settings configuration command
• package.json - Command registration and settings schema
• src/extension.ts - Configuration change listeners and command registration
• src/utils/constants.ts - New command and config constants

Testing

Includes test files demonstrating each rule with intentional violations and correct usage patterns.

[carloseberhardt]

looks good to me