feat: add SEP-10 and SEP-24 anchor integration commands

[Emmy123222]

Overview

StarForge is positioned as a full developer toolkit for Stellar, but had no tooling for Stellar Ecosystem Proposals (SEPs) — the integration protocols every real Stellar application depends on. This PR adds the two most universally needed SEPs: SEP-10 (Web Authentication) and SEP-24 (Hosted Deposits/Withdrawals), along with a shared stellar.toml parser utility.

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What's Changed

src/utils/stellar_toml.rs — Shared stellar.toml Parser

A new utility that fetches and parses https://<domain>/.well-known/stellar.toml, extracting:

• WEB_AUTH_ENDPOINT
• TRANSFER_SERVER_SEP0024
• NETWORK_PASSPHRASE
• SIGNING_KEY

Used by both SEP-10 and SEP-24 flows.

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starforge sep auth — SEP-10 Web Authentication

starforge sep auth --anchor testanchor.stellar.org --wallet alice

Flow:

1. Fetches stellar.toml from the anchor domain → reads WEB_AUTH_ENDPOINT
2. GET WEB_AUTH_ENDPOINT?account=<pubkey> → receives challenge {transaction, network_passphrase}
3. Decodes and verifies the challenge XDR:
   • First operation is manage_data with key "<anchor> auth" and 64-byte nonce
   • Time bounds are present and not expired
4. Computes the Stellar signing hash: sha256(sha256(passphrase) || ENVELOPE_TYPE_TX || tx_body_xdr)
5. Signs with the local wallet key (supports encrypted wallets — prompts for password)
6. Adds DecoratedSignature to the envelope and POSTs back to the anchor
7. Receives JWT and stores it in ~/.starforge/data/sep10_tokens.json keyed by anchor domain

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starforge sep deposit — SEP-24 Hosted Deposit

starforge sep deposit --anchor testanchor.stellar.org --asset USDC --amount 100 --wallet alice

Flow:

1. Loads stored SEP-10 JWT for the anchor (runs sep auth automatically if none stored)
2. Fetches stellar.toml → reads TRANSFER_SERVER_SEP0024
3. POSTs to /transactions/deposit/interactive with Authorization: Bearer <jwt>
4. Opens the returned interactive URL in the system browser (xdg-open on Linux, open on macOS)
5. Polls /transaction?id=<tx_id> every 5 seconds (up to 2 minutes) until completed, error, or failed

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Files Changed

File	Change
src/utils/stellar_toml.rs	New — stellar.toml fetch + parse utility
src/commands/sep.rs	New — SEP-10 auth + SEP-24 deposit implementation
src/commands/mod.rs	Add pub mod sep
src/utils/mod.rs	Add pub mod stellar_toml
src/main.rs	Add Sep to Commands enum, dispatch, and telemetry

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