Use Gradle zip task for binary copy and preserve permissions

[bishiboosh]

What does this PR do?

Fix zip of release binaries by using Gradle zip task and preserving permissions

Issue number, if applicable

FIxes #91

Checklist

• I have read the contributing guidelines.
• I have documented my code if it is included in the public API.
• I have added tests for my code and ran them via ./gradlew check.

[Copilot]

Pull request overview

This PR fixes packaging of the Kotlin/Native release binaries by switching from a custom ZipOutputStream implementation to Gradle’s built-in Zip task, enabling filesystem permission preservation so Linux (and macOS) binaries keep their executable bit when extracted.

Changes:

• Replaces the single custom MakeBinariesZipTask with per-target Gradle Zip tasks.
• Enables useFileSystemPermissions() on the produced archives and keeps a consistent output location/name scheme.
• Removes the now-unused custom zipping task implementation from buildSrc.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
cli/build.gradle.kts	Creates per-target Zip tasks that zip the produced binaries while preserving filesystem permissions (fixing the missing executable bit issue).
buildSrc/src/main/kotlin/com/deezer/caupain/tasks/MakeBinariesZipTask.kt	Deletes the custom zipping task that didn’t preserve executable permissions in the resulting zip entries.

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