Fix Coreum blockchain project

My dApp is already live with an Angular 18 front-end talking to a Node.js + MongoDB API layer, and it relies on a Coreum Rust smart contract.The front-end should require no changes.

Acceptance criteria
• Corrected Coreum contract compiles and deploys without warnings
• All existing methods return expected results against my current test suite
• You provide at least one new test that reproduces each bug and proves the fix
• Updated deployment instructions or migration script for the new contract address

The rest of the stack—Angular 18, Node.js, MongoDB—remains untouched unless your solution demands a small interface adjustment, in which case include the patch.

If you have solid experience debugging Coreum (or CosmWasm) contracts and can turn this around quickly, let’s get started.