v1.1.0

feat: self-test the Layer-2 slug fork against core (v1.1.0)

remove_filter() leaves sanitize_title_with_dashes() callable, so the plugin now
uses core's own current implementation as a live oracle: it diffs the fork against
it on short fixtures (where neither byte cap fires), once per core version. On
divergence it logs + emails, and — with ASG_L2_FAILSAFE defined — falls back to
core's generator (slugs cap at 200) instead of running a drifted copy. Closes the
one silent-rot risk in the design: a future core rewrite of that function now
shouts the hour it happens, instead of surfacing weeks later as a 404 cliff.

• Layer-2 install is conditional on the drift status
• asg_l2_status is autoloaded (the fail-safe reads it on every request)
• README documents the self-test + the new ASG_L2_FAILSAFE constant