ci(actions): update macos version

[Haroenv]

Summary

update macOS version to have a working CI again

Result

Ci passes

Carthage pass seems flaky, may need to remove that one

[Copilot]

Pull request overview

This PR updates the GitHub Actions CI workflows to use newer macOS runner versions and corresponding Xcode versions. It also removes the deprecated carthage-prebuild script that was previously required for Carthage dependency management, and includes a minor refactoring of generic type parameter naming in the core hits extraction functionality.

• Updates macOS runners from version 13 to 14/15 with corresponding Xcode version upgrades (14.2 → 15.2/16.0)
• Removes the carthage-prebuild script and all references to it
• Refactors generic type parameter names from T to Hit for improved code clarity

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
.github/workflows/swift.yml	Updates macOS runner to 15 and Xcode to 16.0 for Swift tests
.github/workflows/pods.yml	Updates macOS runner to 14 and Xcode to 15.2 for CocoaPods linting jobs
.github/workflows/carthage.yml	Updates macOS runner to 15, Xcode to 16.0, removes prebuild step, adds GitHub token
carthage-prebuild	Removes deprecated script that generated Xcode projects for Carthage dependencies
Readme.md	Removes reference to the now-deleted carthage-prebuild script from installation instructions
Sources/InstantSearchCore/Hits/HitsExtractable.swift	Renames generic type parameter from T to Hit for better semantic clarity

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