fix: use Texts$Translation instead of Texts$LiteralText in opTextTemplate

Texts$LiteralText is not a valid Mendix storage type name. The correct
type for text items inside Texts$Text is Texts$Translation with a
LanguageCode field. Also fix empty Parameters version marker (int32(3)
for empty, not int32(2)).

Fixes TypeCacheUnknownTypeException when opening projects with Image
widgets that had text template values set via the pluggable engine.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ako

mdl/executor/widget_engine.go

@@ -236,15 +236,16 @@ func setTextTemplateValue(val bson.D, text string) bson.D {
 						{Key: "$Type", Value: "Texts$Text"},
 						{Key: "Items", Value: bson.A{int32(3)}},
 					}},
-					{Key: "Parameters", Value: bson.A{int32(2)}},
+					{Key: "Parameters", Value: bson.A{int32(3)}},
 					{Key: "Template", Value: bson.D{
 						{Key: "$ID", Value: mpr.IDToBsonBinary(mpr.GenerateID())},
 						{Key: "$Type", Value: "Texts$Text"},
 						{Key: "Items", Value: bson.A{
 							int32(3),
 							bson.D{
 								{Key: "$ID", Value: mpr.IDToBsonBinary(mpr.GenerateID())},
-								{Key: "$Type", Value: "Texts$LiteralText"},
+								{Key: "$Type", Value: "Texts$Translation"},
+								{Key: "LanguageCode", Value: "en_US"},
 								{Key: "Text", Value: text},
 							},
 						}},
@@ -271,7 +272,8 @@ func updateTemplateText(tmpl bson.D, text string) bson.D {
 							int32(3),
 							bson.D{
 								{Key: "$ID", Value: mpr.IDToBsonBinary(mpr.GenerateID())},
-								{Key: "$Type", Value: "Texts$LiteralText"},
+								{Key: "$Type", Value: "Texts$Translation"},
+								{Key: "LanguageCode", Value: "en_US"},
 								{Key: "Text", Value: text},
 							},
 						}})