Abilities API: Unify schema conventions across core abilities

[gziolo]

The three core abilities shipped in 6.9.0 (core/get-site-info, core/get-user-info, core/get-environment-info) have drifted in small but visible ways. This ticket proposes a quality pass so they share a single blueprint.

Proposed Changes

• Every output property should declare both title and description, reusing existing WP Admin translations where possible.
• core/get-environment-info should gain the optional fields input parameter already supported by the other two.
• core/get-user-info should be exposed via REST (show_in_rest => true) so clients can discover it under /wp-json/wp-abilities/v1/abilities.
• Property titles should be normalized to Title Case.

Each change should be accompanied by unit tests so the unified contract is enforced going forward.

## Summary

The three core abilities shipped in 6.9.0 (core/get-site-info, core/get-user-info, core/get-environment-info) drifted in small but visible ways. This PR aligns them on a shared blueprint so they're predictable to consume from REST clients and easier to extend.

• Every output property declares both title and description, reusing existing WP Admin translations where possible.
• core/get-environment-info accepts the optional fields input parameter already supported by the other two, with an enum of valid keys.
• core/get-user-info is exposed via REST (show_in_rest => true) so clients can discover and invoke it under /wp-json/wp-abilities/v1/abilities.
• Property titles are normalized to Title Case. db_server_info is relabeled Database Server Info since \$wpdb->db_server_info() returns vendor+version, not just a version.
• Registration tests lock the exact ordered set of property keys on both the input enum and the output properties, so any future field addition forces a test update.

## Test plan

• [ ] npm run test:php -- --filter=Tests_Abilities_API_WpRegisterCoreAbilities is green
• [ ] core/get-user-info is listed at /wp-json/wp-abilities/v1/abilities for an authenticated user
• [ ] core/get-environment-info accepts {"fields":["php_version"]} and returns only that key
• [ ] Unknown field names on any of the three abilities yield an ability_invalid_input error
• [ ] npm run env:composer -- lint -- src/wp-includes/abilities.php reports no violations
• [ ] npm run typecheck:php passes

🤖 Generated with ​Claude Code

[gziolo]

In 62426:

Abilities API: Unify schema conventions across core abilities

Align core/get-site-info, core/get-user-info, and core/get-environment-info on a shared blueprint: every output property carries a Title Case title and a description, core/get-environment-info gains the optional fields input parameter the other two already accept, and core/get-user-info is exposed via REST. Descriptions are also tightened for programmatic consumers, and registration tests now lock the exact ordered set of property keys.

Props gziolo, westonruter.
Fixes #65355.

[milana_cap]

Dev note published: ​https://make.wordpress.org/core/2026/07/31/abilities-api-improvements-in-wordpress-7-1/