Fix named let: trampoline call_lambda result in sf_named_let

call_lambda returns a thunk (for TCO) but sf_named_let was passing
it directly to the CEK machine without trampolining. The loop body
never executed — set! mutations were lost and the loop returned
immediately.

One-line fix: wrap call_lambda result in trampoline.

All 87 Node tests now pass:
- test-named-let-set.js: 9/9 (was 3/9)
- test-highlight.js: 7/7 (was 1/7)
- test-smoke.js: 19/19
- test-reactive-islands.sx: 22/22
- test-reactive-islands.js: 39/39

Note: server-side source display still empty because the JIT
compiler handles named let differently (VM bytecode path, not
tree-walk). The JIT fix is separate.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/lib/sx_ref.ml

@@ -314,7 +314,7 @@ and is_else_clause test =
 
 (* sf-named-let *)
 and sf_named_let args env =
-  (let loop_name = (symbol_name ((first (args)))) in let bindings = (nth (args) ((Number 1.0))) in let body = (prim_call "slice" [args; (Number 2.0)]) in let params = ref ((List [])) in let inits = ref ((List [])) in (let () = ignore ((if sx_truthy ((let _and = (prim_call "=" [(type_of ((first (bindings)))); (String "list")]) in if not (sx_truthy _and) then _and else (prim_call "=" [(len ((first (bindings)))); (Number 2.0)]))) then (List.iter (fun binding -> ignore ((let () = ignore ((params := sx_append_b !params (if sx_truthy ((prim_call "=" [(type_of ((first (binding)))); (String "symbol")])) then (symbol_name ((first (binding)))) else (first (binding))); Nil)) in (inits := sx_append_b !inits (nth (binding) ((Number 1.0))); Nil)))) (sx_to_list bindings); Nil) else (List.fold_left (fun _acc pair_idx -> (let () = ignore ((params := sx_append_b !params (if sx_truthy ((prim_call "=" [(type_of ((nth (bindings) ((prim_call "*" [pair_idx; (Number 2.0)]))))); (String "symbol")])) then (symbol_name ((nth (bindings) ((prim_call "*" [pair_idx; (Number 2.0)]))))) else (nth (bindings) ((prim_call "*" [pair_idx; (Number 2.0)])))); Nil)) in (inits := sx_append_b !inits (nth (bindings) ((prim_call "inc" [(prim_call "*" [pair_idx; (Number 2.0)])]))); Nil))) Nil (sx_to_list (prim_call "range" [(Number 0.0); (prim_call "/" [(len (bindings)); (Number 2.0)])]))))) in (let loop_body = (if sx_truthy ((prim_call "=" [(len (body)); (Number 1.0)])) then (first (body)) else (cons ((make_symbol ((String "begin")))) (body))) in let loop_fn = (make_lambda (!params) (loop_body) (env)) in (let () = ignore ((set_lambda_name loop_fn (sx_to_string loop_name))) in (let () = ignore ((env_bind (lambda_closure (loop_fn)) (sx_to_string loop_name) loop_fn)) in (let init_vals = (List (List.map (fun e -> (trampoline ((eval_expr (e) (env))))) (sx_to_list !inits))) in (call_lambda (loop_fn) (init_vals) (env))))))))
+  (let loop_name = (symbol_name ((first (args)))) in let bindings = (nth (args) ((Number 1.0))) in let body = (prim_call "slice" [args; (Number 2.0)]) in let params = ref ((List [])) in let inits = ref ((List [])) in (let () = ignore ((if sx_truthy ((let _and = (prim_call "=" [(type_of ((first (bindings)))); (String "list")]) in if not (sx_truthy _and) then _and else (prim_call "=" [(len ((first (bindings)))); (Number 2.0)]))) then (List.iter (fun binding -> ignore ((let () = ignore ((params := sx_append_b !params (if sx_truthy ((prim_call "=" [(type_of ((first (binding)))); (String "symbol")])) then (symbol_name ((first (binding)))) else (first (binding))); Nil)) in (inits := sx_append_b !inits (nth (binding) ((Number 1.0))); Nil)))) (sx_to_list bindings); Nil) else (List.fold_left (fun _acc pair_idx -> (let () = ignore ((params := sx_append_b !params (if sx_truthy ((prim_call "=" [(type_of ((nth (bindings) ((prim_call "*" [pair_idx; (Number 2.0)]))))); (String "symbol")])) then (symbol_name ((nth (bindings) ((prim_call "*" [pair_idx; (Number 2.0)]))))) else (nth (bindings) ((prim_call "*" [pair_idx; (Number 2.0)])))); Nil)) in (inits := sx_append_b !inits (nth (bindings) ((prim_call "inc" [(prim_call "*" [pair_idx; (Number 2.0)])]))); Nil))) Nil (sx_to_list (prim_call "range" [(Number 0.0); (prim_call "/" [(len (bindings)); (Number 2.0)])]))))) in (let loop_body = (if sx_truthy ((prim_call "=" [(len (body)); (Number 1.0)])) then (first (body)) else (cons ((make_symbol ((String "begin")))) (body))) in let loop_fn = (make_lambda (!params) (loop_body) (env)) in (let () = ignore ((set_lambda_name loop_fn (sx_to_string loop_name))) in (let () = ignore ((env_bind (lambda_closure (loop_fn)) (sx_to_string loop_name) loop_fn)) in (let init_vals = (List (List.map (fun e -> (trampoline ((eval_expr (e) (env))))) (sx_to_list !inits))) in (trampoline (call_lambda (loop_fn) (init_vals) (env)))))))))
 
 (* sf-lambda *)
 and sf_lambda args env =