WC: weird networks switch after the app refresh

[elena-zh]

Partially related to #7853

1. Open the app
2. Switch it to Base, as an example
3. Connect to a wallet using WC --> the app picks Ethereum network after connection (Selected network is not picked on a wallet connection #7853)
4. Change the network to Avalanche, as an exmple
5. Refresh the page

One more case:

1. Connect to Rabby on Base, for example
2. Disconnect
3. Switch to Ethereum
4. Connect to a wallet using WC

AR: the app is switched to Base.
Also noticed, that it may switch to another chain while a TX execution (e.g. when a user runs approve TX first, then it may switch to another chain before Swap)

ER: the app is on Avalanche

[linear-code]

FE-303

[tenderdeve]

@elena-zh I'd like to work on this.

[tenderdeve]

@elena-zh dug into this — the switch on refresh comes from how the chain is resolved during reconnect.

On load, useAccountState seeds chainId from the URL (getCurrentChainIdFromUrl()), then subscribes to AppKit state (libs/wallet/src/wagmi/hooks/useAccountState.ts:38-45). When the wallet reconnects, subscribeState fires with the wallet's stored selectedNetworkId and unconditionally overrides the URL chain via setChainId. Then WalletChainUrlSyncUpdater (apps/cowswap-frontend/src/common/updaters/WalletChainUrlSyncUpdater.ts:19-25) writes that wallet chain back into the URL — so after a refresh the app snaps to the wallet's chain rather than the network shown before the refresh.

Net effect: on refresh the wallet's chain always wins over the pre-refresh selection, and there's no concept of 'the chain the user had selected before reconnect', so it looks like a random switch.

Two ways to fix, but the right one is a product call:

1. During the initial reconnect window prefer the URL chain (last user selection), and only accept the wallet's chain for explicit switches made after reconnect.
2. Keep wallet-wins but make the transition non-jarring.

Which precedence do you want on refresh — the pre-refresh app chain, or the connected wallet's chain? This is core reconnect logic shared by every wallet/chain (and overlaps with #7853), so I'd rather confirm the intended behaviour before changing it. Happy to implement once it's settled.