* refactor(extensions): remove dead QA and utility exports
* refactor(extensions): trim Matrix QA internal exports
* chore(deadcode): refresh extension export baseline
* chore(ci): reconcile deadcode and LOC baselines
* chore(deadcode): refresh baseline after main advance
* chore(deadcode): refresh baseline after main advance
* refactor(plugins): keep channel snapshot type private
* fix(ci): align Linux deadcode baseline
