Stage 17 (#14): raise robot early-move band [1,5] -> [3,10] min (slower openings)

backend/internal/robot/strategy.go

@@ -31,8 +31,8 @@ const (
 	// delays near the band's floor — an active player). The result is clamped to
 	// [delayHardMinMinutes, delayHardMaxMinutes]. The numbers are deliberate estimates,
 	// to be retuned once real play statistics arrive (docs/ARCHITECTURE.md §7).
-	delayEarlyLoMinutes = 1.0
-	delayEarlyHiMinutes = 5.0
+	delayEarlyLoMinutes = 3.0
+	delayEarlyHiMinutes = 10.0
 	delayLateLoMinutes  = 10.0
 	delayLateHiMinutes  = 90.0
 	delaySkew           = 4.0

backend/internal/robot/strategy_test.go

@@ -57,8 +57,8 @@ func TestMoveDelayGrowsWithMoveCount(t *testing.T) {
 		return xs[n/2]
 	}
 	for s := int64(1); s <= 500; s++ {
-		if d := moveDelay(s, 0).Minutes(); d < 1 || d > 5 {
-			t.Fatalf("first-move delay %.2f out of [1,5] for seed %d", d, s)
+		if d := moveDelay(s, 0).Minutes(); d < 3 || d > 10 {
+			t.Fatalf("first-move delay %.2f out of [3,10] for seed %d", d, s)
 		}
 		if d := moveDelay(s, 40).Minutes(); d < 10 || d > 90 {
 			t.Fatalf("late-move delay %.2f out of [10,90] for seed %d", d, s)