Summary

This PR adds foundational AST improvements to pmd-kotlin and introduces KotlinAstUtil, a utility class with reusable navigation helpers.

1. Kotlin AST node improvements

• KotlinInnerNode: implement attributes() to get an node-type specific attributes view

• AttributeView: base class to add custom attributes to antlr based nodes

• e.g. KtClassDeclarationAttributes adds the attribute "Identifier"

• attribute implementations can be shared via default methods in interfaces, e.g. HasIdentifier

• New XPath attributes exposed: @Identifier, @Modifiers, @Name on applicable nodes; visible in PMD Designer

• The attribute @Image has been removed. See also Deprecate getImage/@Image #4787.

2. KotlinAstUtil — static navigation utility

New class net.sourceforge.pmd.lang.kotlin.ast.internal.KotlinAstUtil with helper methods for use in Java-based Kotlin rules:

• textOf(KtSimpleIdentifier) — extract text from a SimpleIdentifier node
• textOf(KtPrimaryExpression) — extract text from a PrimaryExpression
• isWithin — scope check: is node n directly inside a given ancestor instance (not inside any intervening node of the same type)?
• collectParamNames — collect parameter names from a KtFunctionDeclaration
• collectLocalVarNames — collect local val/var names in scope
• collectClassVarFieldNames — collect class-level field names
• collectLambdaParamNames — collect explicit lambda parameter names from a KtLambdaLiteral