feat(stellar): implement Horizon path finding with strict receive support and public export (#448)

[s6pa1rta3n-lab]

Summary

Resolves #448. Implements and exports DEX auto-routing primitives querying Stellar Horizon /path/strict-send and /path/strict-receive endpoints with slippage clamping, price impact warnings, TTL expiration handling, and strict-receive operation construction.

Changes

• Public Stellar Export (src/stellar/index.ts):

  • Re-exported all routing members (findStrictSendPath, findStrictReceivePath, buildPathPaymentOp, buildPathPaymentStrictSendOp, buildPathPaymentStrictReceiveOp, validateQuoteExpiry, clampSlippage, ROUTING_CONFIG, RoutedQuote, PathPaymentParams) from the stellar integration layer.

• Routing Infrastructure (src/stellar/routing.ts):

  • Added JSDoc docstrings for public API contracts and functions.
  • Implemented buildPathPaymentStrictReceiveOp constructing Operation.pathPaymentStrictReceive with slippage-adjusted sendMax.
  • Added buildPathPaymentStrictSendOp as an explicit semantic alias to buildPathPaymentOp.
  • Enforced clamped slippage within buildPathPaymentOp and buildPathPaymentStrictReceiveOp.
  • Stripped non-docstring inline comments to keep code self-documenting.

• Unit Testing Suite (tests/unit/stellar/routing.test.ts):

  • Added unit test for buildPathPaymentStrictReceiveOp verifying decoded XDR attributes, sendMax calculation, and destination.
  • Added failure tests for findStrictReceivePath: empty Horizon records (Horizon strict-receive returned no path), malformed source asset format, and malformed destination asset format.
  • Verified alias consistency between buildPathPaymentStrictSendOp and buildPathPaymentOp.

Verification

• npm run lint: Passing with zero errors.
• npx prettier --check src/stellar/routing.ts src/stellar/index.ts tests/unit/stellar/routing.test.ts: Passing.
• npx jest tests/unit/stellar/routing.test.ts: 36/36 tests passing.
• npx jest tests/unit/stellar: 94/94 tests passing across all 11 test suites.

Payout Routing

• EVM (Base/Arbitrum/Polygon/ETH): 0xF46C9F6d70C50BF81ef3588AB523a90a594a2F89
• Stellar: GCL6OXAMLD75BMTINA6EMRUDWK5THQUSHMYNLSNBCJAPZJHNYJTUNIBC