fix(docker): make configureNextcloud work with bind mounted apps

[luflow]

Problem

configureNextcloud() currently aborts on main as soon as an app is bind mounted into apps-writable (which startNextcloud(branch, true) does by default):

chown: changing ownership of '/var/www/html/apps-writable': Operation not permitted

Docker pre-creates the bind mount target as root, but runExec defaults to www-data, which may not chown it.

After fixing that, the next call fails too:

[cause]: { stdout: 'attendance already installed\n', stderr: '', exitCode: 1 }

app:list is queried before apps.config.php registers apps-writable as an apps path, so the mounted app is missing from the list. It is then not found in shipped.json either and ends up in the app store branch, where app:install --force exits non-zero with "already installed".

Both were introduced together with the apps-writable handling; the repo's own test suite passes mountApp: false, so neither is covered.

Fix

• run mkdir/chown for apps-writable as root (same as the existing data directory handling in startNextcloud)
• build the app list only after apps.config.php has been written

Testing

• npm run lint, npm run build, npx tsc --noEmit – clean
• npm run test:node – 4/4 pass (unchanged behaviour, mountApp: false)
• Manually against a bind mounted app (nextcloud/attendance, stable34, macOS + Docker Desktop): configureNextcloud now completes and reports attendance 1.41.2 enabled instead of aborting.

Not verified: whether the chown also failed on Linux runners – this is the one platform dependent spot in the change, and I only had macOS + Docker Desktop available.