chore: track upstream NativePHP Laravel 13 support

[ibourgeois]

Context

As a maintainer, I need Katra to stop depending on a temporary NativePHP compatibility branch once official Laravel 13 support lands upstream so desktop bootstrapping and release builds can move back to a supported package source.

Acceptance Criteria

• The repository tracks the upstream NativePHP Laravel 13 support work explicitly.
• The issue links to the upstream PR so maintainers can check unblock status easily.
• Once upstream support is released, Katra can replace the temporary compatibility-branch dependency with an official NativePHP release.

Notes

Katra currently relies on the temporary NativePHP Laravel 13 compatibility branch noted in the repo docs. Upstream tracking PR:

• NativePHP/desktop PR fix(dist): sign, notarize, and staple macOS desktop builds #96: Laravel 13.x Compatibility NativePHP/desktop#96

This issue is for removing the temporary bridge once that upstream work is merged and released.

Out of Scope

• Reworking Katra's desktop architecture beyond swapping back to an official NativePHP release.
• General NativePHP feature work unrelated to Laravel 13 compatibility.