Add config for enabling the wasm version of shiki highlighter

[amadeus]

This PR adds back the ability to use the WASM highlighter, given there are certain cases (especially in Webkit/Safari) where performance is drastically improved over the JS variant.

I'm keeping it still under the key preferredHighlighter because once we've created one, you can't change the type (it would require a full disposal).

I'm not quite sure what the bundle implications will be here, but i think it should ok...

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Project	Deployment	Actions	Updated (UTC)
pierrejs-diff-demo	Ready	Preview	Feb 9, 2026 11:41pm
pierrejs-docs	Ready	Preview	Feb 9, 2026 11:41pm

[Copilot]

Pull request overview

Adds a configurable way to choose between Shiki’s JavaScript regex engine and the WASM Oniguruma engine across the @pierre/diffs highlighter stack (shared highlighter and worker pool), and updates docs/examples accordingly.

Changes:

• Introduces preferredHighlighter: 'shiki-js' | 'shiki-wasm' and threads it through shared highlighter + WorkerPoolManager initialization.
• Switches worker highlighter initialization to async createHighlighterCore and adds Oniguruma engine support.
• Updates Shiki imports/dependencies to rely on shiki/* entry points and documents the new option in docs/demo.

Reviewed changes

Copilot reviewed 16 out of 17 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/diffs/src/worker/worker.ts	Async worker message handling + engine selection (js vs wasm) during highlighter creation.
packages/diffs/src/worker/types.ts	Adds preferredHighlighter to the worker initialization request/types.
packages/diffs/src/worker/WorkerPoolManager.ts	Stores preferredHighlighter on the pool and passes it into shared highlighter + worker initialization.
packages/diffs/src/utils/getHighlighterOptions.ts	Extends highlighter option derivation to include preferredHighlighter.
packages/diffs/src/types.ts	Defines HighlighterTypes and exposes preferredHighlighter on base code options.
packages/diffs/src/shiki-stream/types.ts	Updates Shiki type import path to shiki/core.
packages/diffs/src/shiki-stream/tokenizer.ts	Updates Shiki type import path to shiki/core.
packages/diffs/src/shiki-stream/stream.ts	Updates Shiki type import path to shiki/core.
packages/diffs/src/renderers/DiffHunksRenderer.ts	Adjusts option typing to exclude preferredHighlighter from required defaults.
packages/diffs/src/highlighter/shared_highlighter.ts	Adds engine selection to shared highlighter creation based on preferredHighlighter.
packages/diffs/package.json	Removes direct @shikijs/* deps now covered by shiki, bumps package version.
bun.lock	Lockfile updates reflecting dependency/version changes.
apps/docs/app/docs/WorkerPool/content.mdx	Documents preferredHighlighter for WorkerPool initialization.
apps/docs/app/docs/WorkerPool/constants.ts	Adds commented examples for preferredHighlighter.
apps/docs/app/docs/VanillaAPI/constants.ts	Documents preferredHighlighter in vanilla usage examples.
apps/docs/app/docs/ReactAPI/constants.ts	Documents preferredHighlighter in React usage examples.
apps/demo/src/main.ts	Demo opts into 'shiki-wasm'.

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