Add Aegis storage layout documentation

[El-swaggerito]

Description

Difficulty: Hard

Type: Documentation

Summary

Document Aegis contract storage layout and migration risks.

Current Behaviour

Storage structures may change without clear documentation of compatibility and migration impact.

Expected Behaviour

The repo should document storage keys, data models, upgrade risks, and review requirements for storage-changing PRs.

Suggested Implementation

Create storage layout documentation and README links.

Files or Areas Likely Affected

• docs/
• README.md
• src/

Acceptance Criteria

• Storage layout documentation is added.
• Key data models are documented.
• Storage-changing PR risks are explained.
• Migration assumptions are documented.
• Review checklist is included.
• README links to storage docs.

Additional Notes

This supports safer protocol development.

[Bahagophilemon]

Hi, I'll take this. I'll document the storage layout, key data models, migration risks, and review checklist, then link it from the README.

[Terryodib]

I will like to work on this issue.

I have experience writing technical documentation for Rust and smart contract projects. I will document the contract's storage layout, key data models, migration and compatibility risks, and review considerations for storage changes, then link the guide from the README to help contributors make safer protocol changes.

[grantfox-oss]

🦊 GrantFox — @Bahagophilemon 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 #168)
2. Your PR will be reviewed by the Axionvera maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@Bahagophilemon's PR #183 was approved and merged by @El-swaggerito.

🏆 @Bahagophilemon: You earned 35 FoxPoints for this contribution! Your current tier: Explorer (188 total points). Track your full progress on GrantFox.

👏 Great work, @Bahagophilemon! Keep contributing to Axionvera.