#277 setf/rotatef/psetf on nested c*r places: undefined SETF-CADDR (FIXED)

FIXED 2026-07-11 commit 455b07d.

(setf (caddr x) V) and any setf/psetf/rotatef/shiftf/incf on a nested c*r place (caar..cddddr) hit 'call to undefined function: SETF-CADDR' — the setf macro's (setf NAME) fallback mangles to SETF- but only setf-car/cdr existed. Added all 28 compound-accessor setf-expanders (setf-caar..setf-cddddr) to src/stdlib.lisp.

Verified: (setf (caddr x) 99) on (1 2 3 4) -> (1 2 99 4); (rotatef (car x) (caddr x)) on (1 2 3) -> (3 2 1); (setf (cadar x) 77) on ((1 2) 3) -> ((1 77) 3). ANSI data-and-control-flow/rotatef.lsp 9->13 PASS. Pure stdlib additions, self-host validated.