[lightbulbman]

Summary

Page caches were storing and replaying responses from the plugin's REST API. With LiteSpeed Cache active, the snippet list re-read after an activation toggle returned stale data until the cache was purged.

Changes

• Add REST_Cache_Bypass, registered with the REST controllers. On rest_post_dispatch, for any route under code-snippets/v*, it:
  • sets Cache-Control, Pragma, Expires, X-LiteSpeed-Cache-Control, X-Accel-Expires, Surrogate-Control, CDN-Cache-Control, Cloudflare-CDN-Cache-Control and X-Cache-Enabled on the response;
  • defines DONOTCACHEPAGE and fires litespeed_control_set_nocache.
• Add the code_snippets/rest_api/bypass_cache filter to switch the behaviour off.
• Append a timestamp query parameter to every GET sent through the shared axios instance.

Routes outside the plugin's namespace are not modified.

Verification

• PHPUnit: new REST_Cache_Bypass_Test; full suite passes on this branch (364 tests, 25 skipped).
• PHPCS and ESLint pass on the changed files.
• Not verified against a server running LiteSpeed Cache or another page cache.