docs(readme): swap order — Spanish first, then English

User feedback: prefer the two language tracks not interleaved. Now the
hero block leads with Spanish (tagline + paragraph), then the English
versions, then badges and the universal architecture diagram. The two
big sections that follow are reordered: 🇪🇸 Español first (full self-
contained section), then 🇬🇧 English. Trailing keyword block kept.

No content changes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: JohanYP