Multi-wallet support via Stellar Wallets Kit (Albedo, xBull, Lobstr, Hana)

[Ryjen1]

Problem

Stellink only supports Freighter today. That excludes anyone who uses Albedo, xBull, Lobstr, Hana, or wants to sign with a Ledger. The wallet-coupling is hard-coded inside useStellarWallet.

Proposal

Migrate the wallet integration to @creit.tech/stellar-wallets-kit, which exposes a unified API across all major Stellar wallets. The kit handles wallet detection, the connect modal, and signing — we keep the rest of our wallet context unchanged.

Acceptance criteria

• Replace @stellar/freighter-api with @creit.tech/stellar-wallets-kit.
• useStellarWallet exposes the same publicKey, connect(), disconnect(), signAndSubmit() surface — no breaking changes to consumers.
• Connect modal lists Freighter, Albedo, xBull, Lobstr, and Hana at minimum.
• Selected wallet persists across reloads (localStorage).
• Disconnect clears the persisted wallet selection.
• Manual smoke test: connect with each of the listed wallets on testnet and submit a payment.

Files involved

• frontend/src/hooks/useStellarWallet.ts — full rewrite around the kit.
• frontend/src/components/WalletButton.tsx — minor tweak to surface the kit's modal.
• frontend/package.json — swap the dependency.

Notes

Keep the kit configured for testnet by default and read the network from STELLAR_NETWORK_PASSPHRASE in configAddress.ts so the existing mainnet/testnet flag still works.