TypeScript SDK Client Auto-Generation

[Luluameh]

Background
Third-party developers building on SkillSphere need typed client bindings rather than raw RPC calls.
Goal
Use soroban contract bindings typescript to auto-generate a typed TypeScript SDK and publish it as an NPM package.
Acceptance Criteria

• GitHub Actions step runs soroban contract bindings typescript post-build.
• Generated SDK committed to sdk/typescript/ directory.
• package.json configured for NPM publish under @skillsphere/contract-sdk.
• README with usage examples for startSession, endSession, rateExpert.
  Key Files
  sdk/typescript/, .github/workflows/soroban.yml, sdk/typescript/README.md