`JniMethodDecl` gains `is_static: bool = false`. parseJniClassDecl's
body loop now recognises a `static` identifier prefix (context-sensitive
— `static` stays a plain identifier elsewhere) and consumes it before
the method name, setting `is_static` on the resulting decl. Dispatch
to `GetStaticMethodID` / `CallStatic*Method` arrives in Phase 2.12.
122/122 examples green.