core: RUST_MIN_VERSION unused export; runtime entry re-exports heavy wasm module

[Dione-b]

Summary

packages/core/src/runtime/requirements.ts:

• RUST_MIN_VERSION (line 4) is never imported anywhere in the repo (grep-verified — only NODE_MIN_MAJOR and CURRENT_RUST_WASM_TARGET are consumed by packages/cli)
• The CURRENT_RUST_WASM_TARGET re-export (line 1) pulls contracts/wasm.ts (crypto, fs, errors) into the runtime entry point

Why it matters

Dead API surface plus a fat entry chunk for a constant-only module used by CLI preflight.

Suggested fix

Delete RUST_MIN_VERSION or consume it (e.g. in the CLI rust diagnostic), and move the wasm target constants to a dependency-free module.

Priority: Low | Release impact: Patch | Breaking: No

[Galmanus]

@Galmanus has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

PR #178. A version constant was exported but never used anywhere. The fix removes it. Full core suite passes.

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