Expose savings fund document fields over REST

[stenehrlich-tuleva]

What

Enable show_in_rest on the group_fund_savings_documents ACF field group so the current TKF document URLs — terms_file, prospectus_file, key_investor_info_file (all return_format => 'url') — are readable via the WordPress REST API:

GET /wp-json/wp/v2/pages?slug=tuleva-taiendav-kogumisfond-dokumendid → .acf.terms_file, …

Why

The onboarding-client drift check needs to compare the documents shown in the savings-fund signing flow against the ones published here. Exposing these fields over REST lets it read them as structured data instead of scraping the rendered page (no fragile filename/label parsing). See TulevaEE/onboarding-client#1555.

Safety

• Additive only — one field-group flag, no template or UI change.
• The exposed values are document URLs that are already public (linked on the public fund-documents page), so no new information is disclosed.
• Deploy remains master-only; merging this and pushing to master is what makes it live.

Refs TulevaEE/TKF-VPII2026#63

🤖 Generated with Claude Code

[stenehrlich-tuleva]

Closing to clear the queue. The one-line show_in_rest flag is genuinely still missing on master, but its consumer is parked: oc#1555 was closed unmerged in May and TKF-VPII2026#63 has not moved since 2026-06-15. Not worth an open PR while nothing reads it. Branch survives, so re-open or re-cut when #63 revives.