File new Missing User Report
Supported formats:
- https://mastodon.social/@username
- https://instance.tld/@username/1234567890 (any post URL)
- https://instance.tld/notice/ABC123 (Pleroma/Akkoma)
- https://instance.tld/objects/ABC123 (Akkoma)
- https://instance.tld/users/username (Akkoma)
Note: Some instances may have API limitations or require authentication.