Add Mac App Store download links and clarify README App Store messaging

[offyotto]

Motivation

• Resolve contradictory README messaging that said the app was not on the Mac App Store while an App Store edition exists.
• Surface a direct App Store download link in the App Store landing, support, and privacy pages so users can reach the approved listing quickly.
• Improve discoverability and reduce brand/installation confusion between the sandboxed App Store build and the direct-download build.

Description

• Added the App Store URL https://apps.apple.com/us/app/core-monitor/id6762558526?mt=12 to the README install section and compatibility notes and removed the contradictory “not available on the Mac App Store” line.
• Updated the Mac App Store landing page (Mac-App-Store/index.html) to include a prominent “Download on the App Store” CTA in the hero and closing actions.
• Added direct App Store download links to Mac-App-Store/support/index.html and Mac-App-Store/privacy/index.html headers and main action areas so support and privacy pages point users at the store listing.
• Files changed: README.md, Mac-App-Store/index.html, Mac-App-Store/support/index.html, Mac-App-Store/privacy/index.html.

Testing

• Ran rg -n "apps.apple.com/us/app/core-monitor/id6762558526\?mt=12|not available on the Mac App Store" README.md Mac-App-Store/index.html Mac-App-Store/support/index.html Mac-App-Store/privacy/index.html and confirmed the App Store URL appears in the intended locations and the contradictory sentence was removed.
• Inspected the updated files with nl -ba to validate CTA placement in the hero and closing sections of Mac-App-Store/index.html and link placements in support/privacy pages.
• Verified working tree changes are present with git status --short and created PR metadata via the project PR tooling for review.

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Codex Task