Recursive `self` not bound during DAG β-reduction

[protocolstardust]

A lambda that calls itself via self evaluates correctly at the top level but fails with error: domain when applied to a column inside select. The DAG's named-lambda inliner treats self as a free variable instead of as a binding to the enclosing lambda.

Reproduction

Reproduced against ~/rayforce head, commit b3e7bdb3.

;; Define a recursive Fibonacci using `self`.
(set fib (fn [x] (if (< x 2) 1 (+ (self (- x 1)) (self (- x 2))))))

;; Direct application — works.
(println (fib 5))           ;; => 8

;; The same lambda inside select against a column — fails.
(set t (table [n] (list (til 6))))
(println (select [n (fib n)] from t))
;; => error: domain

Expected behavior

(select [n (fib n)] from t) should produce a 2-column table where the
second column is [1 1 2 3 5 8] — the per-row application of fib.

The DAG β-reducer must bind self to the lambda being inlined, the same way
direct evaluation does, so a recursive lambda passed into a column expression
behaves identically to one called directly.