Add docker availability check to all scripts that use docker commands

22 scripts used docker without verifying it's present. Consistent with the
pattern already established in Docker_Essentials scripts. Added after acquire_lock
and before detect_hosts in each script's setup section.

Partnership/partnership_offboard.sh

@@ -97,6 +97,11 @@ PARTNERSHIP_LIB_MODE=1 source "$SCRIPT_DIR/partnership_manager.sh"
 # ==============================================================================================
 [[ "$EUID" -ne 0 ]] && { error "Must be run as root"; exit 1; }
 
+if ! command -v docker &>/dev/null; then
+    error "Docker command not found"
+    exit 1
+fi
+
 detect_hosts
 
 OWNER_ID="${PARTNERSHIP_OWNER_HOST:-HOST1}"