Fix lint error

[QUBITABHAY]

This pull request introduces several improvements and refactorings across the authentication, configuration, database, migration, and CI/CD workflow areas of the codebase. The main highlights are a significant refactor of the Google OAuth login flow for clarity and maintainability, improved error handling and logging, modularization of Echo middleware and route setup, and enhanced migration tooling. Additionally, the CI workflow now includes a linting step before build. Below are the most important changes grouped by theme:

Authentication and OAuth Refactor:

• Refactored the Google OAuth login and callback flow in internal/auth/google_login.go to extract logic into helper methods (getUserOrCreateFromOAuth, updateUserOAuthTokens, linkExistingUserToOAuth, createNewOAuthUser), improving readability and maintainability. Also introduced a googleProvider constant and updated token/cookie handling.
• Standardized session and token expiry durations with named constants in internal/auth/providers.go and internal/auth/service.go.

API Server Structure and Error Handling:

• Modularized Echo server setup in cmd/api/main.go by moving middleware and route setup to setupMiddleware and setupRoutes functions. Improved error handling by logging errors and returning early instead of panicking or calling log.Fatal.

Migration Tooling:

• Refactored cmd/migrate/main.go to use structured logging (zap), modularized migration command execution into separate functions (runUp, runDown, etc.), and improved resource cleanup with deferred closures and error handling.

Codebase Documentation and Linting:

• Added package-level documentation comments to internal/auth/google_login.go, internal/config/config.go, and internal/database/connection.go for improved code clarity and maintainability.
• Introduced a lint job to the GitHub Actions workflow (.github/workflows/go.yml) to ensure code quality before building.

Minor Cleanups:

• Minor import ordering and code style improvements throughout several files to align with Go conventions.