Fix CTGov API Connection Issue

[akabishau]

This pull request updates the HTTP client stack to improve compatibility, reliability, and HTTP/2 support, while also ensuring the codebase and tests reflect these changes. The most important changes include pinning gem versions for compatibility, switching the Faraday HTTP adapter to Typhoeus for better HTTP/2 support, and updating test expectations and stubs accordingly.

Dependency and HTTP client updates:

• Pinned the ffi gem to < 1.17.0 to maintain compatibility with Ruby 2.7.7 and RubyGems 3.1.6.
• Updated faraday to version ~> 2.7 and added the faraday-typhoeus gem to enable the Typhoeus adapter with HTTP/2 support.
• Changed the Faraday adapter in app/services/http_client.rb to use :typhoeus with HTTP/2, replacing the default adapter.

Test and spec updates:

• Updated all test stubs and expectations to use the new Faraday user agent string (Faraday v2.8.1) to match the updated gem version.
• Adjusted test expectations in spec/services/http_client_spec.rb to expect a Faraday::TimeoutError instead of Faraday::ConnectionFailed after retries, reflecting changes in error handling with the new adapter.

Documentation updates:

• Improved the README.md for clarity, corrected links, and updated descriptions of the application and download page.

[Copilot]

Pull Request Overview

This PR addresses CTGov API connection issues by switching from Faraday's default adapter to Typhoeus with HTTP/2 support, along with necessary dependency updates and test adjustments.

Key Changes:

• Updated Faraday to v2.7+ and added faraday-typhoeus gem for HTTP/2 support via libcurl
• Switched HTTP adapter from default to Typhoeus with HTTP/2 in the HttpClient service
• Updated all test stubs to reflect new Faraday v2.8.1 user agent string

Reviewed Changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Gemfile	Pinned ffi gem for Ruby 2.7.7 compatibility, updated faraday to ~> 2.7, and added faraday-typhoeus dependency
app/services/http_client.rb	Replaced default Faraday adapter with Typhoeus configured for HTTP/2
spec/services/http_client_spec.rb	Updated expected error type from ConnectionFailed to TimeoutError for retry behavior
spec/models/utils/util_updater_spec.rb	Updated stub headers to match Faraday v2.8.1 user agent
spec/models/clinical_trials_api_v2_spec.rb	Updated all WebMock stubs with new Faraday v2.8.1 user agent string
spec/mailers/notifier_spec.rb	Updated stub headers to match Faraday v2.8.1 user agent
README.md	Improved grammar, fixed download page URL from /snapshots to /downloads

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}