1.0.0 stable

First stable release of the Drupal.org-native LSCache integration.
Cut after rc1 soaked cleanly across TubeSpanner Portal and several
live production sites for ten days with no tag-invalidation
regressions, header correctness issues, or open queue reports.

Same code as rc1 plus a cosmetic info.yml description polish. 1.0.0
signals API stability and opens the project to Drupal Security
Advisory coverage. 1.0.x is now bug-fix and security-patch only;
new feature work moves to 1.1.x.