feat(1): add dynamic solc version resolution

[BartoszSolkaBD]

Summary

• Resolve Solidity compiler versions from pragma or explicit input
• Cache remote solc downloads and improve error messaging
• Add unit coverage for version resolution behavior

Issue

Closes #1

Approach

Centralize version selection in solc-loader by parsing pragma ranges and mapping to the newest compatible release from the official Solidity list, then load via solc.loadRemoteVersion with caching. ContractCompilerService now passes contract content for fallback resolution.

Testing

• Unit: pnpm test:unit -- src/core/utils/__tests__/unit/solc-loader.test.ts
• Integration:
• Manual:
• Not run (explain why):

Risks / Follow-ups

• Remote release list fetch depends on network availability

Checklist

• Scope matches the approved issue
• Acceptance criteria satisfied
• Tests updated or justified
• Docs updated if needed