Define JSON-RPC plugins

[skonves]

This PR implements JSON-RPC plugin support by defining comprehensive schemas and validation functions for parser, validator, and generator plugins. It establishes a standardized communication protocol between the Basketry CLI and plugins using JSON-RPC 2.0 specification.

[Copilot]

Pull Request Overview

This PR implements JSON-RPC plugin support by defining comprehensive schemas and validation functions for parser, validator, and generator plugins. It establishes a standardized communication protocol between the Basketry CLI and plugins using JSON-RPC 2.0 specification.

Key changes:

• Added JSON-RPC request/response schemas for parse, validate, and generate operations
• Extended validation functions to support all plugin types with proper error handling
• Updated package dependencies to stable versions and integrated Basketry build process

Reviewed Changes

Copilot reviewed 4 out of 6 changed files in this pull request and generated no comments.

File	Description
src/validator.ts	Added comprehensive validation functions for all JSON-RPC plugin operations with generic error handling
src/schema.json	Defined complete JSON-RPC schemas for plugin communication including request/response structures
src/index.ts	Updated exports to include all validator functions
package.json	Updated dependencies to stable versions and integrated Basketry into build process

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