chore(ci): improve Nx sandbox cache declarations (#7833)

* chore(ci): establish CI timing baseline

* faster maybe ?

* chore(ci): declare sandbox task inputs and outputs

* chore(ci): declare remaining build sandbox inputs

* another batch

* try fixing e2e import protection

* more sandbox fixes

* fix(e2e): isolate import protection artifacts

* fix script

* fix import protection

* tune even more

* tune even more with some global ignore

* ok, anohter try

* fix(ci): avoid reading captured build logs

* one last improvement for tonight