Add support for @prettier/plugin-oxc parsers

[roryabraham]

Problem

@prettier/plugin-oxc registers oxc and oxc-ts parsers that override Prettier's built-in babel and typescript parsers for JS/TS/JSX/TSX files. Since this plugin only attaches its import-sorting preprocess hook to the babel, typescript, flow, vue, svelte, and ember-template-tag parsers, import sorting is silently skipped when @prettier/plugin-oxc is active.

This is because Prettier auto-detects the parser from the file extension, and when OXC is loaded it maps .ts/.tsx/.js/.jsx to oxc-ts/oxc instead of typescript/babel. The OXC parsers have no preprocess hook, so the sort-imports preprocessing never runs.

Solution

This PR adds oxc and oxc-ts parser entries that compose OXC's parser with the sort-imports defaultPreprocessor. The import of @prettier/plugin-oxc is wrapped in a try/catch so it remains fully optional — if the OXC plugin is not installed, nothing changes.

Changes:

• src/index.ts: Dynamically import @prettier/plugin-oxc (with try/catch fallback) and add oxc/oxc-ts parser entries with preprocess: defaultPreprocessor
• package.json: Add @prettier/plugin-oxc as an optional peerDependency (>= 0.1.0) and as a devDependency for testing

How it works

The preprocess hook operates on source text using @babel/parser to extract and reorder imports, then returns the modified source text. This is independent of the downstream parser (OXC), which receives the already-sorted source. OXC's parse, astFormat, and other properties are preserved via object spread.

Testing

Verified manually:

1. Created a .ts file with deliberately out-of-order imports
2. Ran prettier with both @prettier/plugin-oxc and this patched plugin
3. Imports were correctly sorted according to importOrder config
4. Without the patch, imports were left unsorted