Add contract upgrade state-schema migration safeguards in upgrade-governance

[Emeka000]

Summary

The upgrade-governance contract approves WASM binary upgrades but does not validate that the new binary is backward-compatible with the existing on-chain storage schema. A schema-breaking upgrade can corrupt all patient data silently.

Proposed Design

• Add a schema_version: u32 field to each contract's storage
• Require the new WASM to declare its minimum compatible schema version
• Reject upgrade proposals where the new binary's minimum schema version is greater than the currently stored version (migration required first)
• Add a migrate_schema(from_version, to_version) entry point pattern for contracts with schema changes

Acceptance Criteria

• Schema version is stored and incremented on migrations
• Upgrade proposals include schema compatibility assertion
• Incompatible upgrades are rejected at proposal time
• Migration entry point pattern is documented in the upgrade guide

[CHEF-SAVY]

@CHEF-SAVY has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Gm! I'd like to work on this.

I've gone through the issue and understand what needs to be done. I'll keep the fix scoped, clean, and tested — and communicate clearly if anything comes up along the way.

Ready to start immediately. Feel free to assign it!

ℹ️ Repo Maintainers: To accept this application, review their application or assign @CHEF-SAVY to this issue.

[Mormentz]

@Mormentz has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hi, I can add a schema-safe upgrade layer to upgrade-governance by introducing versioned storage checks that prevent incompatible WASM upgrades from being applied to live contracts.
This will enforce schema_version tracking, validate upgrade compatibility before approval, and require explicit migration paths for breaking changes, ensuring no silent data corruption during upgrades. Safe, backward-aware, and production-grade governance for contract evolution. Ready to start 🚀

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[smog123]

@smog123 has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Hello, i will like to work on this project

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[agnesadoga-creator]

@agnesadoga-creator has applied to work on this issue as part of the Stellar Wave Program's 5th wave.

Kindly assign

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