chore(shellcheck): no new findings in the update skill, lib.sh and install.sh (Issue #72)

CI now shellchecks the update skill's scripts: SC1091 is disabled at their
`source` lines as in the other skills, and the two findings this branch added
(lib.sh's loop_lock.sh source, install.sh's one-item legacy loop) are
disabled at their lines.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.agents/skills/lib.sh

@@ -3284,6 +3284,7 @@ mam_update_admit() {
       return 1 ;;
   esac
   [ -f "$marker" ] || return 0
+  # shellcheck disable=SC1091
   declare -F _mam_lock_holder_state >/dev/null || source "$SKILL_DIR/multi-agent-mux-loop/scripts/loop_lock.sh"
   st="$(_mam_lock_holder_state "$marker")"
   case "$st" in

.agents/skills/multi-agent-mux-update/scripts/post_update.sh

@@ -13,7 +13,7 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 WS="$(cd -P "$SCRIPT_DIR/../../../.." && pwd -P)"
 export WORKSPACE_ROOT="$WS"
 export AGENT_SESSIONS_YAML="$WS/.mam/agent-sessions.yaml"
-# shellcheck source=../../lib.sh
+# shellcheck disable=SC1091
 source "$WS/.agents/skills/lib.sh"
 
 MON=0

.agents/skills/multi-agent-mux-update/scripts/update.sh

@@ -22,9 +22,9 @@ SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 WS="$(cd -P "$SCRIPT_DIR/../../../.." && pwd -P)"
 export WORKSPACE_ROOT="$WS"
 export AGENT_SESSIONS_YAML="$WS/.mam/agent-sessions.yaml"
-# shellcheck source=../../lib.sh
+# shellcheck disable=SC1091
 source "$WS/.agents/skills/lib.sh"
-# shellcheck source=../../multi-agent-mux-loop/scripts/loop_lock.sh
+# shellcheck disable=SC1091
 source "$SKILL_DIR/multi-agent-mux-loop/scripts/loop_lock.sh"
 
 YES=0

deploy/install.sh

@@ -167,6 +167,7 @@ if [ "$REFRESH" -eq 1 ] || [ "${MAM_SKIP_VENV:-0}" -eq 1 ] || ! check_assets_pre
 
   # Migrate legacy root layout for remove.sh into .mam_deploy/ if owned
   mkdir -p .mam_deploy
+  # shellcheck disable=SC2043  # one legacy script left (update.sh went with Issue #72)
   for legacy_script in remove.sh; do
     if [ -f "$legacy_script" ] && grep -Fqx "$legacy_script" "$MANIFEST_FILE" 2>/dev/null; then
       mv -f "$legacy_script" ".mam_deploy/$legacy_script"