fix: use Solid server runtime imports

[Akin01]

Summary

• Compile the component package against solid-js/web/dist/server.js so generated SSR helpers do not resolve through the generic solid-js/web entrypoint.
• Import server-only helpers (ssr, Dynamic) from the server runtime in package source.
• Add an e2e regression that imports and renders @akin01/solid-email with --conditions=browser.

Fixes #6.

Verification

• pnpm --filter @solid-email/render --filter @akin01/solid-email run build
• pnpm --filter @solid-email/render --filter @akin01/solid-email run test
• pnpm --filter @solid-email/render --filter @akin01/solid-email run typecheck
• pnpm exec biome check e2e/integrations.e2e.spec.ts packages/solid-email/tsdown.config.ts packages/render/src/shared/slots.ts packages/render/src/shared/solid-js-web-server.d.ts packages/solid-email/src/components/heading/heading.tsx packages/solid-email/src/components/tailwind/tailwind.tsx packages/solid-email/src/render-shim.d.ts
• pnpm test:e2e
• pnpm typecheck:e2e