fix(pgsql): handle default values for array types in migrations

* update default value quoting logic for PostgreSQL
* add tests for array default value handling

pkg/writers/writer.go

@@ -110,8 +110,12 @@ func SanitizeFilename(name string) string {
 // Examples (bigint):    "0"            → "0"
 // Examples (timestamp): "now()"        → "now()"   (function call – never quoted)
 func QuoteDefaultValue(value, sqlType string) string {
+	value = strings.TrimSpace(value)
+
 	// Function calls are never quoted regardless of column type.
-	if strings.Contains(value, "(") || strings.Contains(value, ")") {
+	if strings.Contains(value, "(") || strings.Contains(value, ")") ||
+		strings.Contains(value, "::") ||
+		strings.HasPrefix(strings.ToUpper(value), "ARRAY[") {
 		return value
 	}
 
@@ -121,6 +125,16 @@ func QuoteDefaultValue(value, sqlType string) string {
 		baseType = baseType[:idx]
 	}
 
+	if isArraySQLType(baseType) {
+		if arrayLiteral, ok := normalizeArrayDefaultLiteral(value); ok {
+			return quoteSQLLiteral(arrayLiteral)
+		}
+	}
+
+	if isQuotedSQLLiteral(value) {
+		return value
+	}
+
 	// Types whose default values must NOT be quoted.
 	unquotedTypes := map[string]bool{
 		// Integer types
@@ -154,7 +168,32 @@ func QuoteDefaultValue(value, sqlType string) string {
 
 	// Everything else (text, varchar, char, uuid, date, time, timestamp, json, …)
 	// is treated as a quoted literal.
-	return "'" + value + "'"
+	return quoteSQLLiteral(value)
+}
+
+func isArraySQLType(sqlType string) bool {
+	return strings.HasSuffix(sqlType, "[]")
+}
+
+func normalizeArrayDefaultLiteral(value string) (string, bool) {
+	switch {
+	case strings.HasPrefix(value, "''{") && strings.HasSuffix(value, "}''"):
+		return value[2 : len(value)-2], true
+	case strings.HasPrefix(value, "'{") && strings.HasSuffix(value, "}'"):
+		return value[1 : len(value)-1], true
+	case strings.HasPrefix(value, "{") && strings.HasSuffix(value, "}"):
+		return value, true
+	default:
+		return "", false
+	}
+}
+
+func isQuotedSQLLiteral(value string) bool {
+	return len(value) >= 2 && strings.HasPrefix(value, "'") && strings.HasSuffix(value, "'")
+}
+
+func quoteSQLLiteral(value string) string {
+	return "'" + strings.ReplaceAll(value, "'", "''") + "'"
 }
 
 // SanitizeStructTagValue sanitizes a value to be safely used inside Go struct tags.