Remove five unused @babel/* devDependencies

[henrymercer]

The five @babel/* packages in package.json are entirely unused by this repository. Removing them resolves a Dependabot deadlock permanently, rather than moving it forward one version.

Why these packages are unused

• Build is esbuild. build.mjs imports esbuild and nothing else; esbuild handles TypeScript and JSX itself, with no Babel transform hook.
• Tests are Vitest, which transforms via esbuild/Vite and handles ESM natively.
• No Babel configuration exists anywhere in the repo — no babel.config.*, no .babelrc*, and no vitest.config.* or jest.config.* that could reference one.
• No Babel imports or API usage in any source, script or config file.
• Linting does not involve Babel. eslint.config.mjs parses with @typescript-eslint/parser; @babel/eslint-parser is not installed, and none of the five is a lint tool.
• Lockfile reverse-edge analysis shows no used package depends on any of the five. Their only inbound edges come from the root manifest and from Babel's own packages; babel-plugin-polyfill-* is reachable only via @babel/preset-env, and the many @babel/core peer edges all originate from plugins that exist solely because those presets pull them in. Neither eslint-plugin-github nor vitest has a Babel dependency.

Impact

Removing them drops 129 of 682 locked packages — roughly 19% of the dependency tree — and 2,011 lines from package-lock.json, with nothing added. That is 111 Babel-named packages (107 @babel/* plus 4 babel-plugin-polyfill-*) and 18 transitive dependencies reachable only through them, such as core-js-compat, regexpu-core and the unicode-*-ecmascript helpers.

dist/ is unchanged, as expected for a dev-only removal: nothing Babel-related was ever bundled. The three dist/*.js matches for "Babel" are esbuild's own generated __toESM interop comment explaining the __esModule check, not bundled Babel code.

Validation

npm ci, npm run lint, check-js, check-json-schemas, npm run find-deadcode and the full Vitest suite all pass.

Notes

• Stacked on Align @eslint/js with ESLint 9 and pin the pair in Dependabot config #1458, which aligns @eslint/js back to ^9.39.5 to match eslint. That pre-existing mismatch made npm install fail with ERESOLVE, so package-lock.json could not be regenerated at all until it landed. Please merge Align @eslint/js with ESLint 9 and pin the pair in Dependabot config #1458 first.

[Copilot]

Pull request overview

Removes unused Babel tooling and its transitive dependency tree, reducing development installation overhead. This is stacked on #1458.

Changes:

• Removes five unused Babel dev dependencies.
• Regenerates the lockfile without 129 Babel-related packages.

Show a summary per file

File	Description
package.json	Removes unused Babel dev dependencies.
package-lock.json	Removes their locked transitive dependencies.

Review details

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• Files reviewed: 1/2 changed files
• Comments generated: 0
• Review effort level: Balanced

[mbg]

Nice