fix(desktop): match macOS app icon corner radius to Apple's grid

[Frooodle]

Description of Changes

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Checklist

General

• I have read the Contribution Guidelines
• I have read the Stirling-PDF Developer Guide (if applicable)
• I have read the How to add new languages to Stirling-PDF (if applicable)
• I have performed a self-review of my own code
• My changes generate no new warnings

Documentation

• I have updated relevant docs on Stirling-PDF's doc repo (if functionality has heavily changed)
• I have read the section Add New Translation Tags (for new translation tags only)

Translations (if applicable)

• I ran scripts/counter_translation.py

UI Changes (if applicable)

• Screenshots or videos demonstrating the UI changes are attached (e.g., as comments or direct attachments in the PR)

Testing (if applicable)

• I have run task check to verify linters, typechecks, and tests pass
• I have tested my changes locally. Refer to the Testing Guide for more details.

[github-actions]

📦 Tauri Desktop Builds Ready!

The desktop applications have been built and are ready for testing.

Download Artifacts:

🍎 macOS Universal: Download Stirling-PDF-macos-universal (.dmg) - 342.3 MB
🪟 Windows x64: Download Stirling-PDF-windows-x86_64 (.exe, .msi) - 264.7 MB

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Built from commit 75e7cdc
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[stirlingbot]

✅ Frontend License Check Passed

All frontend licenses have been validated and no compatibility warnings were detected.

The frontend license report has been updated successfully.

[github-actions]

🚀 V2 Auto-Deployment Complete!

🔗 Direct Test URL (non-SSL) http://54.175.155.236:7679

🧩 Admin portal included - try it at http://54.175.155.236:7679/portal.

This deployment will be automatically cleaned up when the PR is closed.

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[balazs-szucs]

task: [desktop:jlink:jar] mkdir -p frontend/editor/src-tauri/libs
task: [desktop:jlink:jar] cp app/core/build/libs/stirling-pdf-*.jar frontend/editor/src-tauri/libs/
task: Task "desktop:jlink:runtime" is up to date
task: [desktop:jlink:verify] node scripts/verify-bundled-jre.mjs src-tauri/runtime/jre/release
[desktop:jlink:verify] Bundled JRE major: 25 (required >= 25)
task: Failed to run task "desktop:prepare": task: Failed to run task "desktop:assets-car": exit status 1

I get this on this branch. When i run task desktop:dev