Stellar-only conformance test suite

[truthixify]

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

Context

We need parameterized invariant tests proving every public function in the Stellar chain module satisfies its contract. Same idea as a cross-chain suite but scoped purely to Stellar primitives.

Scope

• test/conformance/stellar.test.ts covering deriveStealthKeys, generateStealthAddress, scanAnnouncements, deriveStealthPrivateKey, encode/decode round-trip, view-tag math, signWithScalar
• Each invariant runs against 1000+ generated cases
• Deterministic (no network)
• Run on every PR

Acceptance criteria

• At least 10 invariants covered
• Documentation in test/conformance/README.md
• CI integration
• Any failures filed as security issues (privately)

Files to start with

• sdk/src/chains/stellar/
• test/chains/stellar/