Refactor H3Event to Request conversion for session handling fix (Nuxt JS Boilerplate)

[Bijit-Mondal]

The previous convertToRequest implementation was fragile and failed to correctly forward all necessary request data (cookies), leading to session management issues (refresh-tokens).

This commit refactors the function to be more robust and reliable by:

• Using standard h3 helpers (getRequestURL, readRawBody, parseCookies) for idiomatic conversion.
• Ensuring the full URL, including query parameters, is preserved.
• Explicitly parsing and reconstructing the Cookie header to guarantee session data is passed correctly.
• Using readRawBody and Blob to forward the request body without mutation.
• Replacing the non-standard duplex property with credentials: 'include'.

Checklist for important updates

• Changelog has been updated
• Changes to the version if needed
  • In package.json
  • In package-lock.json
  • In lib/ts/version.ts
• Had run npm run build-pretty
• Had installed and ran the pre-commit hook
• If added a new recipe, I also modified types to include the new recipe in Recipe and allRecipes
• If added a new frontend, I also modified types to include the new frontend in SupportedFrontends and allFrontends if required
• If added a new backend, I also modified types to include the new backend in SupportedBackends and allBackends if required

Remaining TODOs for this PR

• Item1
• Item2

[Bijit-Mondal]

@porcellus @DBozhinovski please review