fix(rspack): refresh http import lockfile redirect

[SyMind]

What changed

Regenerate the http-import lockfile as a single redirect-aware entry:

• https://www.unpkg.com/the-answer now records resolved as the final URL
  https://www.unpkg.com/the-answer@1.0.0/dist/the-answer.js after following
  the unpkg 301 redirect.
• The redundant separate entry for the final URL is removed; the original
  URL's entry is authoritative.
• integrity and content_type are unchanged (the content is identical);
  valid_until is refreshed from the re-fetch.

Why

Follow-up to #502. That PR repaired the frozen lockfile check but kept the
legacy two-entry shape written by the pre-fix Rspack. Since
Rspack #15609, the
HttpUriPlugin preserves the original URL's locked entry through redirects and
records the final resolved URL on it, so a clean regeneration with
frozen: false produces a single entry. This keeps the production build
passing with experiments.buildHttp.frozen enabled by default.

Validation

• pnpm install --filter @rspack-example/http-import... --frozen-lockfile
• pnpm --filter @rspack-example/http-import build (production mode, frozen lockfile enforced)

Related

• fix(rspack): refresh http import lockfile redirect #502 — previous lockfile refresh
• web-infra-dev/rspack#15609 — enforce HttpUriPlugin lockfile integrity in frozen builds