test: align sequenceSeverity test with raised warn/crit thresholds

Commit 4b524ae raised the sequence warn floor 60->80 and crit 80->95 but
left the test asserting the old warn floor: sequenceSeverity(70) now
correctly returns SevOK, so the 70%%->SevWarn case failed. Move it to 85,
squarely in the new 80-95 warn band.

Author: brainexe

internal/pg/triage_test.go

@@ -105,8 +105,8 @@ func TestSequenceSeverity(t *testing.T) {
 	if got := sequenceSeverity(10); got != SevOK {
 		t.Errorf("10%% = %v, want SevOK", got)
 	}
-	if got := sequenceSeverity(70); got != SevWarn {
-		t.Errorf("70%% = %v, want SevWarn", got)
+	if got := sequenceSeverity(85); got != SevWarn {
+		t.Errorf("85%% = %v, want SevWarn", got)
 	}
 	if got := sequenceSeverity(95); got != SevCrit {
 		t.Errorf("95%% = %v, want SevCrit", got)