3f0a3901ca
Bootstrap compiler: - ast.nim: add exprCallArgNames to ekCall for named arg tracking - parser.nim: detect name: value syntax in call args - sema.nim: add resolveCallArgs helper that injects default values for missing params and reorders named args into param order. Parser already parsed default param values; sema now uses them. Selfhost compiler: - ast.bux: add defaultExpr to Param, argName to ExprList - parser.bux: parse = defaultExpr in param list, detect name: value syntax in call arguments - sema.bux: add Sema_ResolveCallArgs with same logic as bootstrap Tests: - _test_named_params verifies defaults, named args, mixed positional+named, and named args with defaults in both compilers. All verifications pass: build, selfhost-loop, test-examples, test-golden.