docs: confirm WordPress 7.1 compatibility

[mehul0810]

Summary

References #243.

• Confirms current stable WordPress 7.1 compatibility in the plugin metadata.
• Adds a concise, undated 1.8.0 changelog entry for the completed compatibility verification.
• Preserves the 1.7.0 stable tag and plugin version; no options, hooks, or runtime behavior change.

Scope and non-goals

This PR is limited to compatibility metadata after validation. It does not change editor integrations, media handling, cache behavior, public APIs, or the release/tag state.

WordPress 7.1 applicability matrix

• @wordpress/components: applicable. Packaged settings Dashboard and Cache tabs render and switch correctly with no console errors.
• Iframed editor and persistent toolbar: Perform has no editor extension integration; a core 7.1 post editor loaded its iframe and toolbar without Perform errors.
• Client-side media processing: not used by Perform.
• SVG Icon API: not used; the admin bundle uses Heroicons.
• jQuery UI 1.14.2: no compatibility regression observed; Perform only adjusts jQuery Migrate on the frontend and a WooCommerce-specific legacy handle.
• Abilities API: not used by Perform.

Validation

• composer lint - pass (91 files)
• composer test - pass (148 tests, 482 assertions)
• composer phpstan - pass (61 files)
• npm run lint - pass
• npm run test:unit - pass (11 suites, 40 tests)
• npm run build - pass
• npm run plugin-zip - pass; packaged readme.txt confirms Tested up to: 7.1
• Isolated WordPress Playground 7.1 / PHP 8.3: installed and activated the packaged ZIP; verified plugin activation, Dashboard, Cache tab, and core editor browser flows.
• Plugin Check 2.1.0 in a separate isolated WordPress 7.1 Playground: the post-edit package no longer reports outdated_tested_upto_header.

Screenshots/artifacts are retained at /private/tmp/perform-243-playground/.playwright-cli/page-2026-08-29T10-06-39-927Z.png, /private/tmp/perform-243-playground/.playwright-cli/page-2026-08-29T10-06-57-986Z.png, /private/tmp/perform-243-playground/.playwright-cli/page-2026-08-29T08-17-14-645Z.png, and /private/tmp/perform-243-playground/.playwright-cli/page-2026-08-29T10-12-51-378Z.png.

Residual risk

The complete Plugin Check scan still reports pre-existing, out-of-scope findings in settings/cache modules (translation comments, escaping, direct database-query, nonce, and offloading checks). They are unchanged by this metadata-only PR and should be tracked separately; no WordPress 7.1-specific defect was demonstrated.

[github-actions]

WordPress Playground Preview

The changes in this pull request can previewed and tested using a WordPress Playground instance.