v0.1.11

Added

• Negotiation self-test. A loopback request (wp_remote_get(), 5-second
  timeout) to a plain-URL permalink with a cached markdown version, sending
  Accept: text/markdown, records whether markdown actually reaches clients in
  the mdf_negotiation_status option (autoload off) as
  {status, checked, detail}. Outcomes: working (markdown returned),
  blocked (200 with text/html — something in front of WordPress is
  serving a cached page), and unknown (request failed, timed out, was
  refused, or returned a non-200 — never reported as blocked). Runs on
  activation, when "Offer markdown to agents" is switched on, on a daily cron
  event, and from a Re-test button on the Settings page; never on a normal
  page load. When a request comes back as HTML while the WP Super Cache adapter
  is registered, the test retries once after a short delay so a just-registered
  adapter propagating through a compiled-config cache is not misreported as
  blocked.
• Honest llms.txt. When the self-test reports blocked, the bundled
  default template is served with its "Machine-readable content" section
  replaced by a neutral, attribution-only "About this file" section. Content
  the owner saved in the editor is always served verbatim; the mismatch is
  surfaced only as an admin warning. Working/unknown serve the template
  byte-for-byte unchanged.
• Bundled WP Super Cache adapter (mdf-supercache-adapter.php). Registered
  by path via WP Super Cache's wpsc_plugins setting on activation and when
  markdown offering is enabled, and removed on deactivation and uninstall.
  Hooks wp_cache_get_cookies_values and appends a fixed literal marker
  (mdfmd) only when Accept: text/markdown is present, giving markdown
  requests their own cache key and making the static supercache gate stand
  aside so the request reaches PHP. No part of the raw header enters the cache
  key. Browser requests return bit-for-bit identical input.
• Settings-page status next to the markdown toggle, with a per-state
  explanation, the WP Super Cache mode/adapter-registration state, and a
  warning when a saved custom llms.txt may still claim markdown serving.

Known limitations

• WP Super Cache Expert (mod_rewrite) mode is not fixed by the adapter:
  Apache serves cached files from .htaccess before PHP runs. The Settings
  status says so, and the README documents the RewriteCond a user needs to
  add. Other page caches, CDNs, and reverse proxies are out of scope — the
  self-test tells those users the truth instead of claiming a fix.
• The self-test requires at least one cached markdown file and a working
  loopback request; otherwise it reports unknown, which is expected.