c: retire TODO-named-let-bytecode.md

Resolved by 45a90b8 (vm restores cur_code across CALL/RETURN).
The reproducer at lines 5-11 of the TODO file runs cleanly now
under both `lumbda --fast` and `lumbda -j --fast`, and the
proof/eml_proof_in_lumbda.lsp `normalize` function no longer
needs the `(define (iter ...))` workaround that the TODO
documented. Future regressions are caught by
tests/regression-named-let-leak.{lsp,sh}.

c/TODO-named-let-bytecode.md

@@ -1,60 +0,0 @@
-# C --fast bytecode compiler: named-let + inner `let`+`if` bug
-
-## Reproduction (minimal)
-
-```scheme
-(define (maybe x) (if (> x 3) #f (+ x 1)))
-(define (g start)
-  (let loop ((t start))
-    (let ((next (maybe t)))
-      (if next (loop next) t))))
-(display (g 0)) (newline)
-```
-
-Expected output: `4`
-
-Actual with `c/lumbda --fast`: hangs or segfaults.
-Tree-walker (`c/lumbda` default) works correctly.
-Python `--fast` and asm tree-walker both work correctly.
-
-## What's special
-
-The bug fires when:
-- Outer named-let: `(let loop ((t ...)) BODY)`
-- Inside BODY: `(let ((next (fn t))) ...)` — another let
-- Inside inner let: `(if next (loop next) t)` — recursive call
-  through an if branch that was reached via an inner let-body
-
-The recursive tail call to `loop` through the nested let + if doesn't
-reach the loop closure. Bytecode emission likely walks the wrong env
-chain or targets the wrong stack slot.
-
-## Workaround
-
-Replace named-let with an internal recursive `define`:
-
-```scheme
-(define (g start)
-  (define (iter t)
-    (let ((next (maybe t)))
-      (if next (iter next) t)))
-  (iter start))
-```
-
-Compiles correctly under `--fast`. Applied to `proof/eml_proof_in_lumbda.lsp`
-for the `normalize` function.
-
-## Where to look
-
-`c/vm.c:344` `SYM_LET` named-let branch emits:
-  `PUSH_ENV, MAKE_CLOSURE, DUP, BIND name, <args...>, CALL/TAIL_CALL`.
-
-Suspected: the lambda body's closure-env capture plus the inner `let`
-PUSH_ENV interact badly when the tail call is behind an `if` whose
-compilation path doesn't POP_ENV back to the closure's expected level.
-
-## Priority
-
-Low for now — workaround lands in every affected .lsp and the other
-three tiers are unaffected. File for cleanup when the C --fast
-refactor happens.