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/gateway-messaging.org

@@ -21,6 +21,8 @@ This replaces the old ~gateway-manager~ skill. The Telegram/Signal platform code
 
 ** Data
 #+begin_src lisp
+(in-package :passepartout)
+
 (defvar *gateway-configs* (make-hash-table :test 'equal)
   "Maps platform name to plist (:token :thread :interval :enabled)")