Fix Toolkit Overriding Semantics

- key: null and key: "****" now mean “remove this row's identity”
  - only "null": true blanks the whole row
  - explicit id remains authoritative on id + key overrides
  - when a row claims a key from another row, the key and lock entry can move with it if the old row
    loses that key

internal/topdata/native.go

@@ -809,13 +809,7 @@ func collectBaseDataset(dataset nativeDataset) (nativeCollectedDataset, error) {
 			lockModified = true
 			return override, nil
 		}
-		cloned := make(map[string]any, len(override)-1)
-		for field, value := range override {
-			if field != "id" {
-				cloned[field] = value
-			}
-		}
-		return cloned, nil
+		return override, nil
 	}
 	validExplicitIDForNewKey := func(key string, rowID int) bool {
 		if key == "" {
@@ -4063,18 +4057,23 @@ func resolveOverrideTarget(datasetName string, override map[string]any, rowByID
 }
 
 func overrideRequestsNullRow(override map[string]any) bool {
-	rawKey, ok := override["key"]
+	value, ok := override["null"]
 	if !ok {
 		return false
 	}
-	if rawKey == nil {
-		return true
-	}
-	typed, ok := rawKey.(string)
-	if !ok {
+	switch typed := value.(type) {
+	case bool:
+		return typed
+	case string:
+		trimmed := strings.TrimSpace(strings.ToLower(typed))
+		return trimmed == "true" || trimmed == "1" || trimmed == "yes"
+	case int:
+		return typed != 0
+	case float64:
+		return typed != 0
+	default:
 		return false
 	}
-	return strings.TrimSpace(typed) == nullValue
 }
 
 func nullifyOverrideRow(row map[string]any, columns []string, rowByKey map[string]map[string]any) {
@@ -4119,12 +4118,14 @@ func updateOverrideRowKey(datasetName string, row map[string]any, expanded map[s
 		return changed, nil
 	}
 	newKey, ok := newKeyValue.(string)
-	if !ok || newKey == "" {
+	if !ok || newKey == "" || strings.TrimSpace(newKey) == nullValue {
 		delete(row, "key")
 		return changed, nil
 	}
+	conflictingID := -1
 	if conflicting, ok := rowByKey[newKey]; ok && conflicting != nil {
-		conflictingID, conflictingHasID := conflicting["id"].(int)
+		var conflictingHasID bool
+		conflictingID, conflictingHasID = conflicting["id"].(int)
 		rowHasID := rowID != 0 || row["id"] != nil
 		if !conflictingHasID || !rowHasID || conflictingID != rowID {
 			delete(conflicting, "key")
@@ -4135,7 +4136,12 @@ func updateOverrideRowKey(datasetName string, row map[string]any, expanded map[s
 	rowByKey[newKey] = row
 	if existingID, ok := lockData[newKey]; ok {
 		if existingID != rowID {
-			return false, fmt.Errorf("dataset %s: key %q is locked to id %d and cannot be rewritten to id %d", datasetName, newKey, existingID, rowID)
+			if conflictingID >= 0 && existingID == conflictingID {
+				lockData[newKey] = rowID
+				changed = true
+			} else {
+				return false, fmt.Errorf("dataset %s: key %q is locked to id %d and cannot be rewritten to id %d", datasetName, newKey, existingID, rowID)
+			}
 		}
 	} else {
 		lockData[newKey] = rowID