Add GitHub Actions workflow for CI with test, lint, and build jobs

[hary-singh]

This pull request adds a new GitHub Actions workflow for continuous integration (CI) to the repository. The workflow automates testing, linting, and building of the project on every push and pull request to the main branch, ensuring code quality and reliability.

New CI workflow:

• Adds a .github/workflows/ci.yml file that defines three jobs:
  • Test: Checks out the code, sets up Go 1.25, caches dependencies, downloads modules, and runs tests with coverage and race detection.
  • Lint: Checks out the code, sets up Go 1.25, and runs golangci-lint to enforce code style and catch common issues.
  • Build: Checks out the code, sets up Go 1.25, builds the project binary, and verifies the binary by running its help command.