Rewrite onboarding prose to a neutral voice

scripts/next_steps.sh

@@ -66,7 +66,7 @@ orchestrator="$workspace_root/$repo_name"
 
 if [ ! -d "$orchestrator/.git" ]; then
     err "orchestrator checkout not found at $orchestrator"
-    note "run 'just clone-orchestrator' (or 'just setup') first."
+    note "required command: just clone-orchestrator"
     exit 1
 fi
 
@@ -119,9 +119,9 @@ if [ "$MODE" != "run" ]; then
     if [ "${#forward_args[@]}" -gt 0 ]; then
         fwd_suffix=" ${forward_args[*]}"
     fi
-    note "Execute via:"
+    note "Command:"
     note "    just run-next-steps${fwd_suffix}"
-    note "Execute inside the orchestrator:"
+    note "Orchestrator command:"
     note "    cd $orchestrator && just contributor-setup${fwd_suffix}"
     exit 0
 fi