The @ (convert) operator was added without test coverage in the CST and AST parsers.

Changes

• CST parser (cst/parser.rs): Added case_convert verifying a @ b produces a BinaryOp::Convert node with the correct token and Ident children. Runs under --features cst.
• AST parser (ast/parser.rs): Added two cases:
  • convert_simple — verifies a @ b lowers to a convert(a, b) call node
  • convert_error_missing_rhs — verifies missing RHS yields UnexpectedEOFDetected

// CST: a @ b → BinaryOp::Convert node
// AST: a @ b → Expr::Call("convert", [a, b])
token(TokenKind::Ident("a")), token(TokenKind::Convert), token(TokenKind::Ident("b"))

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.