1.1.0-alpha1: private-cache mode for authenticated users

First alpha of the 1.1.x track. Extends caching from public-only to
LSCache's per-user private cache. Authenticated user pages, which
1.0.x passed through to PHP, can now be held per-user.

Drupal-native: the response subscriber detects per-user cache
contexts (user, user.permissions, user.roles, session, configurable)
and emits X-LiteSpeed-Cache-Control: private,max-age=N
automatically. Operators do not hand-tag routes or fragments.

Off by default; private cache scales with active users. Default TTL
600s (vs 3600s public default). Status report row warns if private
mode is enabled but .htaccess lacks 'CacheLookup ... private on'.
Sites upgrading from 1.0.x get the new defaults via
lscache_update_8101.

Roadmap order updated: 1.1 is now private cache, 1.2 is ESI. ESI
fragments are private-cached responses at their own URLs, so
private cache is the foundational primitive ESI builds on.