Remove the "AI 连接配置" page under 扩展&增强 together with the theme's
own OpenAI-compatible provider path. AI generation (SEO, summary, tags)
now runs solely on the WordPress AI Client (wp_ai_client_prompt), with
connections configured through WordPress AI Connectors.
- AI.php keeps only the WP AI Client path: no provider config storage,
no theme fallback, no rate limiting
- Drop /ai/status, /ai/settings and legacy /ai/seo-suggest routes plus
their handlers
- Remove dead compat code: AISEO::suggest, AIPrompt::build_seo_prompt
and the front-submit AI assist flow (its buttons were never rendered
and its endpoints were never registered)
- Update SEO schema/meta-box guidance that pointed at the deleted page
- Add ai-config-removal contract test and refresh the toast and
user-features contracts affected by the cleanup
