pluginMenuMiddleware was using activeMenuItems (from manifest registry)
for HTML injection, ignoring items dynamically prepended to pluginMenuItems
by plugins like stats-dashboard that self-inject via register(app). Core
admin pages don't pass dynamicMenuItems to templates, so they emit the
DYNAMIC_PLUGIN_MENU marker — but since activeMenuItems was empty for
external plugins, injection was skipped and the marker stayed as a comment.

Fix: read c.get('pluginMenuItems') post-next for HTML injection instead
of activeMenuItems, so any pre-next middleware additions are included.

chore: release v3.0.0-beta.11

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>