Docs: add a Spanish version of the organization profile README #2

Every flagship repo in this org ships bilingual documentation (README.es.md, CONTRIBUTING.es.md, AGENTS.es.md), but the organization profile itself is English-only — while a large share of the contributor base the org is courting is Spanish-speaking.

Acceptance criteria

• profile/README.es.md created as a faithful translation of profile/README.md.
• A language switcher added at the top of both files.
• Every link in the ES version points to the .es.md variant where one exists.

Where

beyondnetcode/.github, profile/.