[Contracts] Generate and publish Rust doc documentation for all smart contracts

[Penielka]

Description

Smart contract source code has inline Rust documentation comments (///) but no generated docs. Build and publish documentation to GitHub Pages so developers can understand contract interfaces without reading source code.

Definition of Done

• All public contract functions have /// doc comments with parameters and return values
• Module-level documentation for each contract module
• Examples in doc comments that can be tested with cargo test --doc
• cargo doc --no-deps generates clean HTML documentation
• Documentation published to GitHub Pages via CI workflow
• README links to published docs
• Doc comments explain Soroban-specific concepts (env, storage, auth)

Acceptance Criteria

1. cargo doc --no-deps --open shows all public API documentation
2. Doc examples pass with cargo test --doc
3. Published docs accessible at .github.io/AetherMint/contracts
4. Every public function has a doc comment

Files to Modify

• contracts/src/lib.rs — ensure module doc and re-exports are documented
• contracts/src/credentials.rs — add/improve doc comments
• contracts/src/courseMetadata.rs — add/improve doc comments
• contracts/src/governance.rs — add/improve doc comments
• contracts/src/marketplace.rs — add/improve doc comments
• contracts/src/tokenomics.rs — add/improve doc comments
• contracts/src/dynamic_nft.rs — add/improve doc comments
• contracts/src/dna_storage.rs — add/improve doc comments
• contracts/src/attestation_protocol.rs — add/improve doc comments
• contracts/src/user_profile.rs — add/improve doc comments
• contracts/src/credential_registry.rs — add/improve doc comments
• New file: .github/workflows/docs.yml — build and publish docs

[gloskull]

Hello, I have 4 years of experience delivering solutions for projects like this, covering backend, frontend, and smart contract development. After carefully reviewing your requirements, I have a clear understanding of the task and am confident in my ability to deliver a clean, efficient, and thoroughly tested solution on time. I prioritize code quality, maintainability, and industry best practices throughout the development process.
My PR will be submitted in under 10hours.

[clintjeff2]

Hello, I have 6 years of experience working on tasks like this and handling similar challenges across backend, frontend, and smart-contract development. I have carefully read and fully understood the task requirements, and I am confident I can deliver a clean, efficient, and well-tested solution promptly. I always ensure high-quality implementation, maintainability, and adherence to best practices.

Pull request in 5 hours.

[Emmanuel-Ugochukwu1]

Hi, i would like to work on this

[grantfox-oss]

🦊 GrantFox — @Emmanuel-Ugochukwu1 has been assigned to this issue as part of the Official Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #183)
2. Your PR will be reviewed by the AetherEdu maintainers

Good luck! Track your progress on GrantFox.