fix: bound confirmed points and the attempt percentage

WR-05: Confirm clamps the grader's score to the question's current
points, so lowering a question's points no longer lets a confirm store
more than full marks, and Totals caps the percentage at 100 when a
question's points were raised after the attempt was scored.

classes/scoring_test.go

@@ -84,6 +84,7 @@ func TestTotals(t *testing.T) {
 		{[]float64{2, -0.5}, 4, 1.5, 37.5},
 		{nil, 0, 0, 0},
 		{[]float64{1}, 1, 1, 100},
+		{[]float64{3}, 2, 3, 100},
 	}
 	for _, tc := range cases {
 		score, pct := classes.Totals(tc.points, tc.max)