⚠️ [HIGH] Inconsistent Soroban SDK Versions Across Contracts

[ayomideadeniran]

Description

Different contracts use different versions of the soroban-sdk, creating potential compatibility issues.

Current Versions

Contract	SDK Version
contracts/hello-world/Cargo.toml	20.0.0
contracts/counter/Cargo.toml	21.0.6
contracts/stablecoin/Cargo.toml	20.0.0
compile_utils.js (user compilations)	20.0.0 (hardcoded)

Impact

• SDK 21.0.6 has breaking changes from 20.0.0
• All contracts should target the same version for consistency
• User compilations via the browser IDE use 20.0.0 but deployed example contracts may use 21.0.6
• Confusion for contributors about which version is the "standard"

Required Fix

1. Pick a single soroban-sdk version (preferably the latest stable)
2. Update all contract Cargo.toml files to use the agreed version
3. Update BASE_SDK_VERSION in backend/src/routes/compile_utils.js
4. Document the chosen version in the project README

Reference

Identified during full codebase audit of soroban-playground.

[gloskull]

@gloskull has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi, I’d love to work on this issue. I have 4 years of experience across backend, frontend, full-stack, and smart contract development. I understand the task clearly and can deliver a clean, efficient, well-tested solution on time, with strong focus on code quality and maintainability. My PR will be submitted in 12hours

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[drips-wave]

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