fix(jdk-codemodel): resolve declared variable and parameter types to TypeUsage in source AST

[deer]

LocalVariableDeclaration, EnhancedFor, CatchClause, and LambdaParameter were storing source-form type name strings (via .toString() on javac tree nodes) instead of resolved TypeUsage objects, preventing these nodes from participating in type-system analysis.

The fix threads the existing type-resolution context (Trees, CompilationUnitTree, typeResolver) into JdkStatementConverter via a new setTypeContext() method — mirroring the pattern already used by JdkExpressionConverter. A resolveTypeUsage(Tree) helper is added to both converters that follows the same TreePath → TypeMirror → TypeUsage path already used for method return types, field types, and formal parameters. JdkInitializer wires the statement converter into context alongside the expression converter. Node schemas and marshalling are updated accordingly.

var-inferred types and unresolvable types fall back to UnknownTypeUsage, consistent with how the expression converter handles errors.