Ok I did it and it works. @rstockm FYI, here is how I did it :
Install LAMP and open the terminal
Cd to the web root directory
cd /app/data/public
Download the Latest LinkStack Release
LATEST_URL=$(curl -s https://api.github.com/repos/LinkStackOrg/LinkStack/releases/latest \
| grep "browser_download_url" \
| grep "linkstack.zip" \
| cut -d '"' -f 4)
wget -O linkstack.zip "$LATEST_URL"
unzip -o linkstack.zip
rm linkstack.zip
Remove Cloudron’s Default index.php
rm index.php
Fix folder structure
LinkStack is extracted inside a folder named linkstack/.
Move everything to the real web root:
mv linkstack/* ./
mv linkstack/.* ./ 2>/dev/null || true
rmdir linkstack
Fix permissions
chown -R www-data:www-data /app/data/public
Restart the app in Cloudron
Open the URL and follow the LinkStack setup installation guide.