[Bug]: files:scan follows symlink -> endless loop

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

It is similar to https://github.com/nextcloud/server/issues/6395, but more generic, as it also happens with regular storage.

Steps to reproduce

1. copy a backup from linux or Android, which contains symlinks
2. e.g: include -> ../.. (/mnt/raid/gentoo/usr/include/node/deps/uv/include -> ../..)
3. see that on each scan it finds more and more:
   files/tobi/gentoo/usr/include/node/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/v8/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/uv/include/src/src/deps/v8/include/deps/uv/include/deps/uv/include/deps/uv/include/deps/v8/include/src/deps/v8/include/deps/v8/include/deps/uv/include/v8-profiler.h

This way I have now 44 million entries, while only ~800.000 files are on disk

Expected behavior

Do not follow symlinks, but treat them as regular files

Installation method

None

Nextcloud Server version

27

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response

Start at the files:scan entry point and trace how scanned filesystem entries are classified; the issue provides no file or test path. Reproduce with a symlink such as include -> ../.., then verify scanning treats the symlink as a regular file without traversing it or creating repeated entries.