blog: expand 'extend existing systems with AI' post (all 7 locales)

[xuyushun441-sys]

Why

The first version of /blog/extend-existing-systems-with-ai read like a feature summary, not a story — no concrete scenario, no real coding-agent prompt, no worked 'ask a question → what happens' example. This expands it into a substantive post and keeps all 7 locales in parity (English is source of truth).

What changed

Rewrote the English source and regenerated all 6 translations (zh-Hans, ja, de, es, fr, ko):

• Concrete scenario — a 40-table Postgres CRM and the leadership ask, framed as rebuild (6 months) vs. connect (an afternoon).
• Real Claude Code prompt for generating objects from the connected schema, plus a sample ObjectSchema.create output in the hotcrm shape.
• Worked query example — a natural-language question compiled to ObjectQL → SELECT … WHERE … on Postgres, run as the signed-in user, illustrating capability-aware pushdown.
• Rebuild vs. connect comparison table + a day-one benefits section.
• FAQ — model every table?, production writes, data egress, schema changes.

Accuracy held

• Credentials from env vars only; read-only path emphasized.
• In-product federation kept as roadmap (ADR-0015, Proposed) — the shipped path (connect → model with a coding agent → bind → query) is what's documented as working today.

Verification

pnpm --filter docs build → green. 509 static pages; blog routes generate for every locale (/en/blog/…, /zh-Hans/blog/…, /ja/blog/…, etc.).

Note on Fumadocs blog i18n

Confirmed the blog i18n wiring already follows the official Fumadocs pattern — i18n passed to the loader(), getPages(lang) / getPage(slug, lang) / generateParams(), and per-locale *.<locale>.mdx files. No code changes needed there.