When controlUiBasePath is set, classifyControlUiRequest returned
method-not-allowed (405) for all non-GET/HEAD requests under basePath,
blocking plugin webhook handlers (BlueBubbles, Mattermost, etc.) from
receiving POST requests. This is a 2026.3.1 regression.
Return not-control-ui instead, matching the empty-basePath behavior, so
requests fall through to plugin HTTP handlers. Remove the now-dead
method-not-allowed type variant, handler branch, and utility function.
Closes#31983Closes#32275
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>