Update Knip schema URLs to v6

[Nick2bad4u]

Summary

• update Knip JSON configurations from the v5 schema to the current major-scoped v6 schema
• associate JSONC filenames with Knip's dedicated JSONC schema
• keep all four existing supported configuration filenames without matching JavaScript or TypeScript configs

Evidence

• https://knip.dev/reference/configuration
• https://knip.dev/overview/configuration
• https://unpkg.com/knip@6/schema.json
• https://unpkg.com/knip@6/schema-jsonc.json

Knip's official documentation recommends the @6 URLs. A major-scoped URL receives compatible v6 schema updates without silently crossing into a future breaking v7 release. The project currently has 11.8k GitHub stars and 44.3M npm downloads over the most recent complete 30-day measurement window (measured July 23, 2026).

Validation

• npm clean-install
• npm run typecheck
• npm run eslint
• targeted Prettier formatting
• SchemaStore PR audit (expected catalog-only warning only)
• live HTTP and JSON checks for both upstream schema URLs
• repository-wide node ./cli.js check passes catalog preconditions, then reaches the existing Windows-only Ajv stack overflow while compiling unrelated cargo-lints-clippy.json

[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.