Validate presence of host for HTTP/HTTPS URLs in Automatic::Http

[id774]

Motivation

• Ensure the HTTP helper refuses malformed HTTP/HTTPS strings that contain no host so the framework does not attempt an unintended network request or produce unclear internal errors.

Description

• Add a host presence check to Automatic::Http.uri that raises ArgumentError with a clear message when an http/https URL has no host, and normalize the parsed URI as before.
• Add spec coverage in spec/lib/automatic/http_spec.rb for URLs without a host and update fetchable? expectations accordingly.
• Update doc/VERSIONS and file timestamps to reflect the change.

Testing

• Ran rspec spec/lib/automatic/http_spec.rb to exercise the Automatic::Http behavior and the new examples, and the test run passed.

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Codex Task