fix(common): skip bun relation fields when building valid columns

Fields tagged rel:, join: or m2m: were registered as columns (e.g. rel:has-many),
which broke the 'all' filter expansion with invalid SQL.

pkg/common/validation.go

@@ -49,6 +49,11 @@ func (v *ColumnValidator) buildValidColumns() {
 			continue
 		}
 
+		// Relation fields are not columns
+		if isBunRelationTag(field.Tag.Get("bun")) {
+			continue
+		}
+
 		// Get column name from bun, gorm, or json tag
 		columnName := v.getColumnName(field)
 		if columnName != "" && columnName != "-" {
@@ -57,6 +62,18 @@ func (v *ColumnValidator) buildValidColumns() {
 	}
 }
 
+// isBunRelationTag reports whether a bun tag describes a relation (rel:, join:, m2m:)
+// rather than a database column.
+func isBunRelationTag(tag string) bool {
+	for _, part := range strings.Split(tag, ",") {
+		part = strings.TrimSpace(part)
+		if strings.HasPrefix(part, "rel:") || strings.HasPrefix(part, "join:") || strings.HasPrefix(part, "m2m:") {
+			return true
+		}
+	}
+	return false
+}
+
 // getColumnName extracts the column name from a struct field's tags
 // Supports both Bun and GORM tags
 func (v *ColumnValidator) getColumnName(field reflect.StructField) string {