fix: use the classic JSX runtime for the Vite 8 dep scan (#262) - #363

Fixes #262 on the 2.x line. Backport of 3257a97 (already on next / @solidjs/vite-plugin 3.0.0-next).

Problem

For Vite 8+ the plugin set optimizeDeps.rolldownOptions.transform.jsx: 'preserve' so the Rolldown scanner would not inject react/jsx-dev-runtime imports. But the scanner re-parses the transformed output as plain JS (Vite's vite:dep-scan:transform:js-glob even force-tags glob-containing modules as moduleType: 'js'), so any .tsx with JSX failed with PARSE_ERROR: Unexpected JSX expression. The whole scan aborted and pre-bundling was skipped:

(!) Failed to run dependency scan. Skipping dependency pre-bundling. Error:   Failed to scan for dependencies from entries:
  .../index.html
  [PARSE_ERROR] Unexpected JSX expression
   ╭─[ src/bug.tsx:4:9 ]

Fix

Use the classic JSX runtime for the scan transform (jsx: { runtime: 'classic' }). It lowers JSX to bare React.createElement calls without injecting any import; the scan output is never executed, it only exists so rolldown can walk the import graph, so the undefined identifier is harmless.

Note for anyone testing locally: the string form jsx: 'classic' (as tried in the issue thread) is not a valid rolldown option and fails with Invalid jsx option. It has to be the object form.

Verification

Packed this branch (pnpm pack) and installed the tarball in a minimal project (vite 8.3.0, solid-js 1.9.15) with a .tsx that calls import.meta.glob and returns JSX:

• Published 2.11.14: vite optimize --force and vite dev fail with the parse error above.
• This branch: vite optimize --force pre-bundles solid-js, solid-js/web, solid-js/store, solid-js/html, solid-js/h; the dev server serves the file with the glob expanded; vite build succeeds.

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