feat: add JSON Schema generation with Zod v4

[aryasaatvik]

Summary

This PR adds JSON Schema generation for mcp_servers.json using Zod v4 for runtime validation and schema generation.

Changes

New Files

• src/config-schema.ts - Zod schemas for mcpServers config validation
• scripts/generate-json-schema.ts - Script to generate JSON Schema using Zod's toJSONSchema()
• mcp_servers.schema.json - Auto-generated JSON Schema file

Modified Files

• src/config.ts - Uses Zod safeParse() for runtime validation
• src/errors.ts - Removed unused configMissingFieldError() helper
• package.json - Added zod dependency and generate:schema npm script
• README.md - Added $schema references to config examples
• mcp_servers.json - Added $schema reference
• tests/config.test.ts - Updated tests
• tests/errors.test.ts - Removed configMissingFieldError test
• tests/integration/cli.test.ts - Fixed macOS path normalization

Key Features

1. Zod v4 Integration: Uses Zod v4's native toJSONSchema() method
2. Runtime Validation: Config validated at runtime using Zod's safeParse()
3. Schema Generation: Run npm run generate:schema to regenerate
4. IDE Support: Add "$schema": "./mcp_servers.schema.json" for IDE validation

Tests

All 121 tests pass (93 unit + 28 integration)

Breaking Changes

None. Backward-compatible addition.

[philschmid]

Hey,

What is the benefit here?