Fixes SeoHead (title/canonical/hreflang/JSON-LD) to render during SSR via
vite-react-ssg's Head component instead of a client-only useEffect, so
crawlers see real tags without executing JS. Also fixes an SSR crash in
useTheme (localStorage access with no window during server render) and
removes now-duplicated static meta tags from index.html.
Also fixes a Windows-specific bug in worker.js and cleanup.js: the
"run only if executed directly" guard compared import.meta.url against
`file://${process.argv[1]}`, which never matches on Windows (backslash
path separators, missing extra slash before the drive letter). main()
silently never ran, so the worker process started and exited
immediately without ever polling. Caught during this task's manual
verification of the full upload-convert-download flow. Fixed with
node:url's pathToFileURL, which builds a correct file:// URL cross-platform.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
anthony
