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

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

step-04-signer/getAddress.ts

@@ -0,0 +1,32 @@
+/**
+ * Step 4 — Derivation / Signer: getAddress resolver
+ * Target: ledger-live libs/coin-modules/coin-*/src/signer/getAddress.ts
+ *
+ * Uses @ledgerhq/coin-framework getAddressWrapper. For Ethereum family the
+ * existing Ethereum getAddress resolver applies; ensure currency/chainId 138
+ * is used when resolving for Defi Oracle Meta Mainnet.
+ *
+ * Example resolver shape (adapt to your coin-framework version):
+ */
+
+import type { GetAddressFn } from "@ledgerhq/coin-framework/bridge/getAddressWrapper";
+import type { SignerContext } from "@ledgerhq/coin-framework/signer";
+import type { GetAddressOptions } from "@ledgerhq/coin-framework/derivation";
+import type { EthereumAddress, EthereumSigner } from "./types-signer";
+
+const resolver = (
+  signerContext: SignerContext<EthereumSigner, EthereumAddress>
+): GetAddressFn => {
+  return async (deviceId: string, { path, verify }: GetAddressOptions) => {
+    const address = (await signerContext(deviceId, (signer) =>
+      signer.getAddress(path, verify)
+    )) as EthereumAddress;
+    return {
+      address: address.address,
+      publicKey: address.publicKey,
+      path,
+    };
+  };
+};
+
+export default resolver;