docs: link i18n guide to recipe and dynamic routes (#9256)

[shubhransh-gupta]

Fixes #9256

Summary

• Add ReadMore callout linking the routing guide to the i18n recipe
• Document dynamic-route option for unprefixed default locales with SSR caveat

Test plan

• Docs site builds locally

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Warnings reference

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[shubhransh-gupta]

Hi — gentle ping for review 👋

Addresses #9256 with cross-links from the i18n guide to the recipe (per maintainer preference over merging files). CI is green (Generate Lunaria Overview, triage, Welcome First Time Contributors).

Happy to apply any localization follow-ups if needed. Thanks!