Cross-chain unified wallet adapter

[truthixify]

Tier: M (2-4 days) | Type: feature

Context. PR #149 unified scanning across chains, but signing still requires per-chain wallet plumbing (Freighter for Stellar, viem for EVM, @solana/wallet-adapter for Solana). Apps that hold funds on more than one chain rebuild the same adapter shim every time. src/chains/stellar/signer.ts already defines the pattern for Stellar (StellarStealthSigner, FreighterStealthSigner, WebAuthnPasskeyStealthSigner); Wave 8 lifts that pattern into a cross-chain WalletAdapter union so one registry can drive signing across every supported chain.

Scope.

• WalletAdapter per-chain interface with signMessage, getAddress, chain.
• Reference adapters: Freighter, viem, @solana/wallet-adapter (feature-detected, not required deps).
• New deriveStealthKeysFromWallet(adapter) router (net-new symbol) picks the correct per-chain derivation.
• Example: examples/multichain-scan/ extended to sign across two chains from one adapter registry.

Acceptance.

• Interface exported from src/index.ts
• Reference adapters live behind optional peer-dep guards (no hard imports)
• Example runs on futurenet + a testnet EVM chain end-to-end
• Passkey signer (PR feat(stellar): add signer interface for passkey stealth key derivation #153) implements the interface as validation

Files. src/wallet/adapter.ts (new), src/wallet/adapters/{freighter,viem,solana}.ts (new), src/chains/stellar/signer.ts, examples/multichain-scan/.

[Hallab7]

@Hallab7 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I would love to work on this issue

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[xtrial01]

@xtrial01 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi maintainer, I can fix this issue

Kindly assign

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[annacodervibe]

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I would love to work on this issue, already reviewed the description and have experience with it , please assign me

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[cythecode]

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I will like to work on this issue. Feel free to assign.

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[drips-wave]

Congratulations, @Hallab7! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @Hallab7: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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