feat: add ARC mainnet account/asset detection (MetaMask#9006)

## Explanation

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This PR adds Arc mainnet account API client-side support. 

Account API endpoints that seem to be already working on Arc:
v4 MultiAccount -
https://accounts.api.cx.metamask.io/v4/multiaccount/balances?accountAddresses=eip155%3A0%3A0x13b7e6EBcd40777099E4c45d407745aB2de1D1F8&networks=5042

V1 account relationship -
https://accounts.api.cx.metamask.io/v1/networks/5042/accounts/0x13b7e6ebcd40777099e4c45d407745ab2de1d1f8/relationships/0x80e3d8E7CA14C83432b8Cd860D0c21A97973509C

V1 Account tx history
-https://accounts.api.cx.metamask.io/v1/accounts/0x13b7e6EBcd40777099E4c45d407745aB2de1D1F8/transactions?networks=5042

## References

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## Checklist

- [ ] I've updated the test suite for new or updated code as appropriate
- [ ] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [ ] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/processes/updating-changelogs.md)
- [ ] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/processes/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Additive allowlist entries only; no changes to balance, auth, or
detection logic beyond enabling Arc alongside existing networks.
> 
> **Overview**
> Adds **Arc mainnet** (chain `5042` / `0x13b2`) to the
assets-controllers network allowlists so clients can use Accounts API v4
balances and token detection on Arc.
> 
> `SupportedTokenDetectionNetworks` gains an `Arc` entry in
`assetsUtil.ts`, and `SUPPORTED_NETWORKS_ACCOUNTS_API_V4` in
`constants.ts` includes `0x13b2`. The unreleased changelog records both
additions.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
1c7d0ec. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: gabrieledm <gabriele.delmonte-ext@consensys.net>
Co-authored-by: Gabriele Del Monte <37625739+gabrieledm@users.noreply.github.com>

Author: maxime-oe

packages/assets-controllers/CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- Add `ARC` support ([#9006](https://github.com/MetaMask/core/pull/9006))
+  - Add `ARC` in `SupportedTokenDetectionNetworks`
+  - Add `ARC` in `SUPPORTED_NETWORKS_ACCOUNTS_API_V4`
+
 ### Changed
 
 - Bump `@metamask/transaction-controller` from `^67.0.0` to `^67.1.0` ([#9066](https://github.com/MetaMask/core/pull/9066))

packages/assets-controllers/src/assetsUtil.ts

@@ -160,6 +160,7 @@ export enum SupportedTokenDetectionNetworks {
   Sei = '0x531', // decimal: 1329
   MonadMainnet = '0x8f', // decimal: 143
   Hyperevm = '0x3e7', // decimal: 999
+  Arc = '0x13b2', // decimal: 5042
 }
 
 /**

packages/assets-controllers/src/constants.ts

@@ -20,6 +20,7 @@ export const SUPPORTED_NETWORKS_ACCOUNTS_API_V4 = [
   '0x531', // 1329
   '0x8f', // 143
   '0x3e7', // 999 HyperEVM
+  '0x13b2', // 5042 Arc
 ];
 
 /** Lowercase ERC-20 address for MetaMask USD (mUSD), same contract on listed chains. */