Classify 5 unclassified (category,action) pairs in appEventFrictionClass — false user-facing fallthrough

Found during EVO-62/VENUS-274 telemetry-quality follow-up. vFrictionClassified defaults any (category,action) pair with no row in appEventFrictionClass to frictionClass='user-facing' (isUnclassified=true) — this is a DEFAULT-FALLTHROUGH, not a real classification. 5 pairs are currently falling through and being counted as user-facing friction despite being server-side/system error-log events with no route/UI context: category='app' action='crearPracticaFailed' (x12), 'getPracticaByIdFailed' (x10), 'clientWindowError' (x3), 'clientPageError' (x2), category='security' action='getFrictionDigest' (x1). Fix: add explicit non-user-facing classification rows for these 5 pairs to appEventFrictionClass so future friction-digest/EVO-62-style campaigns don't misclassify system error logs as user friction. Distinct from VENUS-275 (advisory-log mislabeling) — different mechanism, same broad telemetry-quality theme.