Remove Kaktus browser (archived/unavailable repository)

[Copilot]

The Kaktus browser entry referenced a GitHub repository (azer/kaktus) that is now an empty public archive, making the listing effectively dead.

After investigation, the entry is already absent from applications.json and README.md in the current base branch — it was removed in a prior commit. No code changes were required; this PR confirms the removal is in place.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Kaktus browser is no longer available.</issue_title>
<issue_description>When I went to the Kaktus browser link, it said that the repository was empty. Searching for it on Github does bring me to a non-empty repository, but it's a public archive: https://github.com/azer/kaktus

Pull Request #748 removes it, but the PR was closed. I'm not sure if the change was denied or if there was a mistake, but I thought it'd be worth bringing it to attention.</issue_description>

<agent_instructions>Remove Kaktus from applications.json</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Kaktus browser is no longer available. #755

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