Re-enable cargo test in CI (stellar-xdr arbitrary mismatch)

[Miracle656]

Summary

cargo test is currently disabled in .github/workflows/ci.yml because stellar-xdr 20.1.0 transitively expects arbitrary >= 1.4 (uses the details submodule and try_size_hint method) but our resolved arbitrary is 1.3.x, causing fresh CI builds to fail with E0433 / E0407.

Local works because cargo's incremental cache hides the issue.

Files

• .github/workflows/ci.yml
• contracts/Cargo.toml
• contracts/Cargo.lock

Acceptance criteria

• Choose one fix:
  • Add [patch.crates-io] arbitrary = "=1.4.x" to workspace Cargo.toml
  • Or upgrade soroban-sdk / stellar-xdr to a version with consistent arbitrary deps
  • Or add a Cargo.lock patch / yank pin
• cargo test -p invisible-wallet -p factory passes on a clean CI runner
• Re-enable the cargo test line in ci.yml
• Document the fix in CHANGELOG.md

[ezedike-evan]

Hi, I would like to work on this issue. I will investigate the dependency tree to determine the cleanest fix between patching arbitrary to 1.4.x in the workspace Cargo.toml, upgrading soroban-sdk or stellar-xdr to a version with consistent arbitrary dependencies, or applying a lock file pin, and implement whichever approach resolves the conflict without introducing new version mismatches. I will verify that cargo test passes cleanly for both invisible-wallet and factory on a fresh CI runner with no incremental cache before re-enabling the cargo test line in ci.yml. I will also document the root cause and the chosen fix in CHANGELOG.md so future contributors understand why the pin or upgrade exists and do not accidentally revert it. Can I be assigned?

[Miracle656]

Plan looks thorough — go ahead, you're assigned. Please verify the fix works on a fresh runner (no cargo cache) before re-enabling the CI line.