refactor(debug): move watchpoint slot state into the session

debug/debug_test.go

@@ -275,8 +275,7 @@ func TestBreakpointInfo(t *testing.T) {
 }
 
 func TestWatchpointSlotTracking(t *testing.T) {
-	wpSlots = [4]bool{} // reset
-	s := &Session{}
+	s := &Session{} // per-session slots start free
 
 	// All four slots are free initially.
 	for i := range 4 {
@@ -289,8 +288,8 @@ func TestWatchpointSlotTracking(t *testing.T) {
 	}
 
 	// Manually mark slots 0 and 2 as used (simulating successful SetWatchpoint).
-	wpSlots[0] = true
-	wpSlots[2] = true
+	s.wpSlots[0] = true
+	s.wpSlots[2] = true
 
 	if !s.IsWatchpointSlotUsed(0) {
 		t.Error("slot 0 should be in use")
@@ -318,7 +317,7 @@ func TestWatchpointSlotTracking(t *testing.T) {
 
 	// Mark all slots used: FindFreeWatchpointSlot returns -1.
 	for i := range 4 {
-		wpSlots[i] = true
+		s.wpSlots[i] = true
 	}
 	if got := s.FindFreeWatchpointSlot(); got != -1 {
 		t.Errorf("FindFreeWatchpointSlot() with all slots used = %d, want -1", got)