Remove the unused, unmaintained `serde_yaml` dependency

[Darkdruce]

Summary

serde_yaml is declared but used nowhere in src/ or tests/.

Location

• Cargo.toml:32 — grep serde_yaml src tests → no usages.

Details & impact

serde_yaml is officially deprecated/unmaintained (RustSec advisory territory), adds attack surface and audit noise for zero benefit.

Suggested fix

Delete the dependency.

Acceptance criteria

• serde_yaml is removed and the build still passes.

[DANeiraGarcia]

Hello! I can handle this. I'll remove the unused serde_yaml dependency from Cargo.toml, ensure the codebase compiles perfectly without it, and clean up any unused imports if they exist. May I be assigned to this issue?

[grantfox-oss]

🦊 GrantFox — @DANeiraGarcia has been assigned to this issue as part of the Official Campaign | FWC26 campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #146)
2. Your PR will be reviewed by the StellarGateLabs maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Official Campaign | FWC26 campaign!

@DANeiraGarcia's PR #184 was approved and merged by @Manuel1234477.

🏆 @DANeiraGarcia: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (131 total points). Track your full progress on GrantFox.

👏 Great work, @DANeiraGarcia! Keep contributing to StellarGateLabs.