Add full Chain 138 integration: 8 steps, chain spec, app-ethereum config, docs

Co-authored-by: Cursor <cursoragent@cursor.com>

step-08-manual-tests/run-checklist.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# Step 8 — Manual test checklist runner (prints steps; no automation)
+# Usage: ./run-checklist.sh
+
+set -e
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+echo "=== Ledger Chain 138 Manual Test Checklist ==="
+echo "Run each item in Ledger Wallet (desktop or mobile) with Defi Oracle Meta Mainnet."
+echo ""
+cat "${SCRIPT_DIR}/test-plan.md"
+echo ""
+echo "=== End of checklist ==="