[Context7] Support JSON Schema documents

### Problem Description Context7 currently supports ingesting documentation from GitHub, GitLab, Bitbucket, Other Git repositories, OpenAPI specs, LLMs.txt files, and Websites. However, there is no support for JSON Schema documents as a source type. Many libraries and APIs distribute their contracts and data models as JSON Schema files (e.g., $schema: "http://json-schema.org/draft-07/schema#"), and developers working with these schemas cannot get structured, up-to-date context from them through Context7. ### Proposed Solution Add a new JSON Schema adapter as a supported source type alongside the existing ones (OpenAPI, LLMs.txt, Website, etc.). This adapter would: - Accept a JSON Schema document (or URL pointing to one) as a library source - Parse the schema structure (properties, definitions/$defs, required fields, types, descriptions, examples, $ref references) - Convert the schema into Context7's standardized snippet format (codeSnippets and infoSnipp