Stellar federation address resolution helper

[truthixify]

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

Context

Stellar federation (name*domain.com) is a standard way to address Stellar accounts via DNS-resolvable strings. Stealth payment senders may want to use federation addresses; add a helper.

Scope

• resolveStellarFederation(input: string): Promise<{ accountId, memo? }>
• Looks up https://<domain>/.well-known/stellar.toml
• Parses federation endpoint, queries it
• Cache resolutions (default 1 hour)
• Returns typed structure or throws decoded error

Acceptance criteria

• Helper + tests with mocked HTTP
• Integration test against a known testnet federation
• Caching documented + configurable
• Demo follow-up to surface in Send form input

Files to start with

• New: sdk/src/chains/stellar/federation.ts
• Stellar federation SEP-0002