Pull Request: CI/CD Pipeline Optimizations

Summary

This PR introduces several enhancements to the CI/CD pipeline for the SubTrackr project:

Parallel test execution using a matrix strategy with sharded Jest runs.
Build caching for Node modules and Rust dependencies.
Incremental Rust builds that only trigger when contract sources change.
Deployment optimizations: added canary deployment, promotion to production, and rollback jobs in release.yml.
Fixed package.json syntax errors and added a test:shard script.
Added cross-env as a devDependency to simplify environment variable handling.

Updated .github/workflows/ci.yml to run TypeScript tests in parallel shards and upload per‑shard coverage.
Refactored .github/workflows/release.yml to include canary, promote, and rollback jobs, and removed duplicate definitions.
Fixed JSON formatting in package.json, added missing commas, simplified the test:shard script, and added cross-env.
Ran npm install --legacy-peer-deps to resolve dependency conflicts.
Created a new branch ci-optimizations and pushed the changes.

npm ci runs successfully after the fixes.
Sharded tests execute correctly with npm run test:shard (environment variables are now handled via cross-env).
GitHub Actions workflow runs pass, confirming caching and incremental builds work as intended.

#241