Update `soroban.toml` brand name and merge with `Makefile`/`deploy.sh

[P3az3]

Problem Statement soroban.toml declares name = "orbitchain-campaign". The README says "MilestoneX." Makefile and deploy.sh reference the wrong WASM name. There is a brand drift across all three artifacts.

Expected Outcome Set name = "milestonex-campaign" (or however Soroban CLI 26.x prefers the casing). Update all artifacts to use the same canonical name.

Acceptance Criteria

• cargo run -p milestonex-tools -- network reports the correct contract namespace.
• A search confirms no remaining orbitchain references.
• Makefile and deploy.sh deployed binary name matches soroban.toml.

Implementation Notes

• The brand is "MilestoneX"; check any corporate naming guideline before locking in.

Affected Files / Modules

• soroban.toml
• Makefile
• deploy.sh, scripts/deploy.sh
• README.md
• Any other reference

Dependencies — None.

[coderolisa]

Hello Maintainer,

I'd like to work on this issue. I've reviewed the requirements and can complete the implementation as specified.

Please assign it to me. Thank you!

[grantfox-oss]

🦊 GrantFox — @coderolisa has been assigned to this issue!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #40)
2. Your PR will be reviewed by the MillestoneX maintainers

Good luck! Track your progress on GrantFox.