fix: add (in-package :passepartout) to 5 skill files missing it

Eliminates COMMON-LISP-USER::DEFSKILL and other package-related
STYLE-WARNINGs during compilation. Files affected:
- gateway-messaging, programming-repl, programming-standards,
  system-memory, system-archivist
Remaining warnings are cross-skill references (vault functions)
and minor same-file forward refs — category 2 per ROADMAP.

org/programming-repl.org

@@ -36,6 +36,8 @@ The REPL skill fills this gap by:
 ** Global State
 ;; REPL-VERIFIED: 2026-05-03T13:00:00
 #+begin_src lisp
+(in-package :passepartout)
+
 (defvar *repl-package* :passepartout
   "Default package for REPL evaluations.")