feat(wordpress): settings page with PDF links report, page scoping and account check

[bendersej]

Background

The WordPress plugin's settings page showed a single text field. Admins could not tell which PDFs the plugin takes over, could not try it on one page before going live, and did not know where filled PDFs go.

Changes

• WordPress plugin settings page, rebuilt with native WP admin styling:
  • PDFs on your site: every page and post whose content links a PDF, with where each link opens (SimplePDF, browser, or an error) and why, plus a Get started state when there are none; a light-orange header when links need attention
  • Where it runs: everywhere (default, unchanged behaviour) or only on picked pages and posts, drafts included, to test before going live
  • AI assistants: a checkbox in Where it runs; the editor's form tools are offered to in-browser AI assistants (WebMCP), on by default like the script tag
  • Account card: what an account adds, or the linked account with a check that it exists
  • Guides: links to the help center
• One-time review notice on the settings screen once a linked account exists and a PDF link opens in SimplePDF; dismissible for good (nonce-checked AJAX)
• uninstall.php removes every option the plugin stores
• @simplepdf/web-embed-pdf 1.9.0 is bundled, byte-identical to npm; the release ships its source without its tests
• Plugin CI: PHP 5.6 and 8.3 lint, the PHP link rule asserted against the web package's shared link cases, and a drift guard that re-vendors the pinned package from npm and fails on any difference or a wrong SIMPLEPDF_WEB_EMBED_VERSION

Notes

• Verified in WordPress Playground. Screenshots and recordings are on the internal PR (SimplePDF/simple-pdf#415).
• 1.2.0 listing: readme rewritten (outcome-led description, settings previews, FAQ, External services disclosing the editor frame and the account check), settings screenshot retaken, version 1.2.0 in the plugin, readme and blueprint, tested up to WordPress 7.1.2. The changelog says WebMCP is on by default after the update.
• Before the SVN release: the submissions dashboard screenshot (screenshot 1).