fix(chat): Solana and Base wallets get mixed up in the connect UI

[VickyXAI]

Reported from production: Solana and Base get confused in the wallet UI. Two separate causes, both in the wallet facade.

1. An EVM wallet silently masked a connected Solana one

The active chain resolved as evmConnected ? "evm" : solanaConnected ? "solana" : null — EVM wins, unconditionally. And nothing ever enforced the "one active wallet" invariant that the same comment described: connectSolana never disconnected the EVM wallet, connectEvm never disconnected the Solana one.

Both stacks auto-reconnect on mount. So for anyone who had ever connected MetaMask, wagmi restored it, and connecting Phantom afterwards did nothing visible: the pill kept showing Base, the EVM address and the Base balance, and payments kept routing to blockrun.ai. The user explicitly chose Solana and the UI said otherwise.

The stated rationale — "EVM wins the tie because it is the payable chain" — also stopped being true when Solana payments shipped.

• connectEvm / connectSolana now disconnect each other, but only after the wallet says yes, so a declined prompt leaves the previous wallet alone.
• The chain the user last deliberately connected on is persisted and decides the tie, so re-authorizing a wallet from inside an extension can't override a deliberate choice.
• Switching chains clears the server session up front. Sign-in is best-effort, so without this a declined SIWS left the previous wallet's cookie serving its history next to the new wallet's address.

2. The pill flashed the wrong chain on every reload

wagmi has settled by first paint while the Kit plugin is still restoring a persisted wallet. So a returning Phantom user watched the pill resolve to their EVM wallet and only then flip to Phantom.

isReady existed for precisely this, and was plumbed all the way through to useAuth without a single consumer. Now, while Solana is still warming and Solana is the remembered choice, the facade reports "not connected yet" rather than the other chain, and ConnectWallet holds its existing loading shell until isReady.

The remembered chain also moved from an effect to the first client render — it is needed the moment the warm-up resolves, not a commit later. Hydration is unaffected: it only changes the outcome when both wallets are connected, which cannot be true on the first render.

Solana is now the default

It leads the network chooser and wins the untouched tie. That case is only reached when both wallets auto-reconnected without the user picking either, where the tie should fall to the chain we want people on. It is also the cheaper rail — Base adds a $0.001/call transaction fee that Solana's facilitator absorbs.

Also

Renames two flags that now lie: onBase in the connected pill and isOnBase from useUsdcBalance are both true for a connected Solana wallet. They mean "on the network we can transact on", and a name that says Base invites the exact mix-up being reported.

Verified

• All six (evmConnected × solanaConnected × remembered) combinations resolve to the user's last deliberate choice; the two that were wrong before are the two reported symptoms.
• Browser: connect button settles to enabled after warm-up (gating on isReady would otherwise be an excellent way to disable it forever), chooser lists Solana first, Solana → wallet-list flow intact, no console errors.
• typecheck / eslint src / build clean.

Not covered

The real two-wallet case still needs a human with both MetaMask and Phantom installed: connect one, connect the other, confirm the pill, balance and payment routing all follow the wallet you just approved, and that history does not leak across the switch.