Bump IntelliJ version to 2026.1; drop support for <251

Author: AB-xdev

gradle.properties

@@ -5,8 +5,8 @@ pluginName=
 pluginVersion=
 # IntelliJ Platform Properties -> https://plugins.jetbrains.com/docs/intellij/tools-gradle-intellij-plugin.html#configuration-intellij-extension
 platformType=IU
-platformVersion=2025.3.1.1
-platformSinceBuild=243
+platformVersion=2026.1
+platformSinceBuild=251
 # Plugin Dependencies -> https://plugins.jetbrains.com/docs/intellij/plugin-dependencies.html
 # Example: platformBundledPlugins = com.intellij.java, com.jetbrains.php:203.4449.22
 platformBundledPlugins=