[product-pages] Dutch translation pass + re-enable nl locale

[rubenvdlinde]

Source: AUDIT-product-pages-2026-05-13.md fleet audit · feedback_i18n-requirement.md · ADR-030

The migration PR re-enables the nl locale in docusaurus.config.js and scaffolds i18n/nl/. This issue tracks the actual translation pass.

Scope

Every EN markdown that lands in the canonical folders needs a Dutch counterpart:

• intro.md
• installation.md
• All files in Features/
• All files in UseCases/
• All files in Integrations/
• All files in Technical/
• All files in user-guide/

NL writing rules (from design-system/CLAUDE.md)

• Address the reader as je / jij, never u.
• Banned words: Digitale transformatie, Ketensamenwerking, Toekomstbestendig, State-of-the-art, Platform dat…, Synergie, Proactief meedenken, Kernel, Oplossing (as generic product term).
• No em-dashes. Comma, period, or short follow-up sentence instead.
• <16 words per sentence.
• Sentence-case headings.

Acceptance

• Every EN page has an NL counterpart in i18n/nl/docusaurus-plugin-content-docs/current/.
• docusaurus.config.js locale dropdown switches without SSR errors.
• Build passes for both locales (npm run build then npm run build -- --locale nl).