Add Emmet and ESLint suppressions schemas

[Nick2bad4u]

Summary

• Add a new JSON Schema for Emmet snippet files at src/schemas/json/emmet.json.
• Register emmet.json in the catalog for snippets*.json and snippets_*.json filename patterns.
• Add a new JSON Schema for ESLint bulk suppressions at src/schemas/json/eslint-suppressions.json.
• Register eslint-suppressions.json in the catalog for the default ESLint suppressions filename.
• Add positive and negative fixtures for both schemas.

Sources

• Emmet customization format was based on Emmet snippets structure and local snippet usage.
• ESLint suppressions format was based on the official ESLint bulk suppressions docs and the packaged ESLint SuppressionsService typedef: Record<string, Record<string, { count: number }>>.

Validation

node ./cli.js check --schema-name=emmet.json

node ./cli.js check --schema-name=eslint-suppressions.json

• Targeted Prettier check/write on touched schema, catalog, and fixture files.
• Confirmed �slint-suppressions.json matches only the new catalog entry.
• Validated a real generated suppressions file from C:/Repos/UserStyles/eslint-suppressions.json against the new schema.

[github-actions]

Thanks for the PR!

This section of the codebase is owned by @madskristensen and @hyperupcall - if they write a comment saying "LGTM" then it will be merged.