feat(withdraw): withdraw soUSD on Base

[MayankMittal1]

Lets soUSD withdrawals run through Base instead of Ethereum, behind EXPO_PUBLIC_SOUSD_BASE_WITHDRAWALS. It is off by default, so merging changes nothing until the flag is set.

With the flag on

• Step 1: bridges soUSD from Fuse to Base (EID 30184) through the Fuse BridgePaymaster.
• Step 2: queues the shares on the Base queue (0x204b…21e2) for Base USDC. The copy reads "Bridge to Base" and "USDC on Base".
• Already on Ethereum: shares already bridged there still finish on Ethereum. That includes resumed withdrawals that older builds saved, which have no chain recorded. Cancel uses the chain the request was made on.

Always on (production config)

• Base vault addresses: the vault, teller, accountant and queue on Base are in ADDRESSES.base. QA has no Base contracts, so QA builds stay on Ethereum unless the EXPO_PUBLIC_BASE_SOUSD_* overrides are set.
• soUSD on Base in savings:
  • it shows in the wallet and merges into the soUSD coin
  • it is priced at the accountant rate
  • it counts toward the savings balance, not wallet cash
• Base withdraw status, read on-chain: Base has no subgraph, so the status comes from the queue.
  • Processing while the request ID is in getRequestIds(), re-checked every minute.
  • Success once it leaves the queue, or Cancelled if the user cancelled it in the app.
  • Known gap: a request the cron cancels after its deadline also shows as Success, because the queue doesn't record which way a request left.
  • A queued Base request can be cancelled from its activity screen.
• Savings deposit-fee notice: it now asks the backend about soUSD on every chain, because only the backend knows whether soUSD deposits are on Ethereum or Base.

Rollout

Turn the flag on only after the backend's Base solver doc is in place and the Base vault holds a USDC buffer. Until then, Base requests would never be solved, or the solve would revert. The contracts side is live: the Fuse teller is peered with Base, the vault's transfer hook is set, and the roles are configured.

Testing

• Fork simulation of the full flow on anvil forks of Base and Fuse against the live contracts: bridge, queue request, solve, user cancel and cron cancel. The status read returned the right value at each step.
• Jest, one file at a time:
  • useWithdraw, soUsdWithdrawStatus (new), depositFee
  • useActivity.freshness (adds four Base status cases)
  • portfolio, vaultWalletBalance, AssetsOverview, savingsFundTokenGroups
  • alchemyTokenPrices, cardSpendable, withRefreshToken, three BuyFuse suites
  • all passing
• tsc --noEmit and eslint are clean on the changed files.

🤖 Generated with Claude Code

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2 Skipped Deployments

Project	Deployment	Actions	Updated
solid-app	Ignored		Oct 8, 2026 3:37pm UTC
solid-app-staging	Ignored		Oct 8, 2026 3:37pm UTC

[claude]

Code review

No issues found. Checked for bugs and CLAUDE.md compliance.