Handle SSLError and ParsingError in error wrapping

[delano]

Summary

• Add rescue clauses for Faraday::SSLError and Faraday::ParsingError in HttpClient
• Order SSLError before ConnectionFailed (SSLError is a subclass)
• Non-JSON error responses now handled gracefully (returns response_body: nil)

Test plan

• Verify SSL failures raise ConnectionError with descriptive message
• Verify parsing errors raise Error with underlying cause
• Verify non-JSON 500 responses return proper HttpRequestError with nil body

[gemini-code-assist]

Code Review

This pull request enhances the SDK's error handling by explicitly rescuing SSL and parsing errors within the HTTP client, updating the error hierarchy documentation, and adding comprehensive test coverage for these scenarios. The review feedback suggests improving the parsing error rescue by preserving the original exception cause and utilizing a more specific error class to maintain consistency with the rest of the library's error structure.