Document that Syncthing may need extra permissions to access some paths on macOS

Does your log mention database corruption?

No

Required information

• which version of Syncthing and what operating system you are using
  • macOS 12.3
• browser and version, if applicable
  • N/A
• what happened
  1. Browsed to the install and auto instructions ( https://docs.syncthing.net/users/autostart.html#macos )
  2. Ran brew install syncthing
     • It was successful. I got the following prompt:

       To start syncthing now and restart at login:
       brew services start syncthing
       

  3. brew services start syncthing => ==> Successfully started syncthing (label: homebrew.mxcl.syncthing)
  4. Configured it in the WebUI and added my device
  5. Had consistent errors in the UI:
     • Failed to create path for auto-accepted folder ... operation not permitted
     • Failed to create older root directory mkdir ... operation not permitted
     • Error on folder ... folder path missing
  6. Attempted troubleshooting by creating folders and changing folder/file permissions. This did change the errors, which felt like progress.
  7. Attempted troubleshooting by stopping the service and starting syncthing in terminal. This worked, which makes sense now but was confusing at the time.
  8. Found https://forum.syncthing.net/t/scanner-operation-not-permitted/15329 and gave the service full disk permissions. This solved it
• what you expected to happen instead
  • Expected To start syncthing now and restart at login: to be followed by After it starts, you will likely have to allow full disk permissions in "macOS Peferences" > "Security" > “full disk access”
  • Alternately, having it documented on https://docs.syncthing.net/users/autostart.html#macos
  • Further possibility: Clearly state the permission issue in the Web UI. Have you allowed disk access in the Security tab?
• any steps to reproduce the problem
  • See above

Start with the macOS section of docs/users/autostart.html, linked from the issue, and review the reported Homebrew service behavior and permission errors. Update the documentation to explain that Syncthing may need macOS Full Disk Access for some paths, then verify the page builds and the guidance is clear.