feat: add cctp for non-usdc sample app

cctp-non-usdc/.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?

cctp-non-usdc/README.md

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+# Non-USDC Crosschain Transfer Sample
+
+This sample application shows how to transfer non-USDC assets with CCTP, using EURC, cirBTC, or a registered custom token. The recommended path is `@circle-fin/bridge-kit` in `src/main.ts`. If Bridge Kit is not an option, swap to `src/direct.ts` for the same UI against a direct CCTP flow: approve, Iris quote, `crossChainTransfer`, and destination forwarding.
+
+Developer documentation at: https://developers.circle.com/cctp/expanded-assets
+
+## Run
+
+```bash
+bun install
+bun run dev
+```
+
+Connect an injected EVM testnet wallet and choose a token. **EURC** and **cirBTC** load source chains from the Iris registry for that token; destinations are the other chains from that same result (one registry read per token). **Custom token ID** waits for a valid bytes32 ID, then loads sources the same way. Source and destination are always different chains. Leave **Recipient** blank to mint to the connected wallet, or enter another EVM address.
+
+The app submits transactions only after the user presses **Transfer** and approves the wallet prompts. Use a testnet wallet and test tokens while exploring the example.
+
+## Structure
+
+```text
+src/
+  main.ts                 # Bridge Kit entrypoint
+  direct.ts               # Direct CCTPx entrypoint (no Bridge Kit)
+  chains.ts               # Hardcoded CCTPx testnet catalog (direct path)
+  ui.ts                   # Shared form / wallet / Iris registry helper
+  style.css
+vite.config.ts             # Local testnet IRIS proxy
+```
+
+`main.ts` takes its chain list from the CCTPx provider. `direct.ts` uses the hardcoded catalog in `chains.ts` (domain + CCTS + `viem/chains`). Both rely on `ui.ts` for Iris token→chain filtering and destination derivation.
+
+Swap implementations in `index.html`:
+
+```html
+<script type="module" src="/src/main.ts"></script>
+<!-- or -->
+<script type="module" src="/src/direct.ts"></script>
+```
+
+The testnet Iris proxy is for local development. A deployed app needs an equivalent same-origin `/iris/testnet` proxy.

cctp-non-usdc/index.html

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+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <meta name="description" content="Sample app for non-USDC CCTP transfers with Bridge Kit or direct CCTP flow." />
+    <title>Non-USDC Crosschain Transfer Sample</title>
+  </head>
+  <body>
+    <header>
+      <h1>Non-USDC Crosschain Transfer</h1>
+    </header>
+    <main>
+      <p>
+        Transfer non-USDC assets with CCTP, using EURC, cirBTC, or a custom
+        token. Developer documentation at:
+        <a href="https://developers.circle.com/cctp/expanded-assets" target="_blank" rel="noopener noreferrer"
+          >CCTP for non-USDC assets</a>.
+      </p>
+
+      <button id="connect-wallet" type="button">Connect wallet</button>
+
+      <form id="transfer-form">
+        <div class="row">
+          <label class="transfer__token-kind">
+            <span>Token</span>
+            <select id="token-kind">
+              <option value="EURC">EURC</option>
+              <option value="cirBTC">cirBTC</option>
+              <option value="custom">Custom token ID</option>
+            </select>
+          </label>
+
+          <label class="transfer__token-id">
+            <span>Token ID</span>
+            <input id="token-id" type="text" placeholder="Alias token ID" spellcheck="false" readonly />
+          </label>
+
+          <label class="transfer__amount">
+            <span>Amount</span>
+            <input
+              id="amount"
+              type="text"
+              inputmode="decimal"
+              placeholder="0.00"
+              required
+            />
+          </label>
+        </div>
+
+        <div class="row">
+          <label class="transfer__source-chain">
+            <span>Source chain</span>
+            <select id="source-chain" required>
+              <option value="">Choose a source</option>
+            </select>
+          </label>
+
+          <label class="transfer__destination-chain">
+            <span>Destination chain</span>
+            <select id="destination-chain" required>
+              <option value="">Choose a destination</option>
+            </select>
+          </label>
+
+          <label class="transfer__recipient">
+            <span>Recipient</span>
+            <input
+              id="recipient"
+              type="text"
+              placeholder="0x..."
+            />
+          </label>
+        </div>
+
+        <button id="transfer-button" type="submit" disabled>Transfer</button>
+      </form>
+
+      <pre id="transfer-status" aria-live="polite"></pre>
+    </main>
+    <!-- Bridge Kit: /src/main.ts — CCTP flow: /src/direct.ts -->
+    <script type="module" src="/src/main.ts"></script>
+  </body>
+</html>

cctp-non-usdc/package.json

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+{
+  "name": "cctp-non-usdc",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@circle-fin/adapter-viem-v2": "^1.20.1",
+    "@circle-fin/bridge-kit": "^1.17.1",
+    "viem": "^2.57.17"
+  },
+  "devDependencies": {
+    "typescript": "~7.0.2",
+    "vite": "^8.3.7"
+  }
+}

cctp-non-usdc/src/chains.ts

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+import type { Chain } from "viem";
+import {
+  arbitrumSepolia,
+  arcTestnet,
+  avalancheFuji,
+  baseSepolia,
+  hyperliquidEvmTestnet,
+  inkSepolia,
+  optimismSepolia,
+  polygonAmoy,
+  sepolia,
+  worldchainSepolia,
+} from "viem/chains";
+
+/** Sandbox CrossChainTokenService — same CREATE3 address on every CCTPx testnet. */
+export const TESTNET_CCTS =
+  "0x63753E722bd2C2A5DF6EE19C5106662208B81077" as const;
+
+/**
+ * Hardcoded CCTPx testnet catalog for the direct (non–Bridge Kit) path.
+ * Token configuration still comes from Iris — this is chain + CCTS only.
+ */
+export interface CCTPXChain {
+  name: string;
+  chainId: number;
+  cctp: { domain: number };
+  cctpx: { serviceAddress: typeof TESTNET_CCTS };
+  viemChain: Chain;
+}
+
+function cctpxChain(
+  name: string,
+  domain: number,
+  viemChain: Chain,
+): CCTPXChain {
+  return {
+    name,
+    chainId: viemChain.id,
+    cctp: { domain },
+    cctpx: { serviceAddress: TESTNET_CCTS },
+    viemChain,
+  };
+}
+
+/**
+ * CCTPx-enabled EVM testnets — keep in sync with Bridge Kit's
+ * CCTPXBridgingProvider testnet catalog (`serviceAddress` present).
+ */
+export const CCTPX_TESTNET_CHAINS: readonly CCTPXChain[] = [
+  cctpxChain("Ethereum Sepolia", 0, sepolia),
+  cctpxChain("Avalanche Fuji", 1, avalancheFuji),
+  cctpxChain("OP Sepolia", 2, optimismSepolia),
+  cctpxChain("Arbitrum Sepolia", 3, arbitrumSepolia),
+  cctpxChain("Base Sepolia", 6, baseSepolia),
+  cctpxChain("Polygon Amoy", 7, polygonAmoy),
+  cctpxChain("World Chain Sepolia", 14, worldchainSepolia),
+  cctpxChain("HyperEVM Testnet", 19, hyperliquidEvmTestnet),
+  cctpxChain("Ink Sepolia", 21, inkSepolia),
+  cctpxChain("Arc Testnet", 26, arcTestnet),
+];