An account that moves shows where it went

PrivaPub dropped Move as an unknown type and showed no `moved` on accounts.
Now a Move is believed as Mastodon believes it: the moving account sends it
about itself, and the new account, read again from its own server, names it
in alsoKnownAs (now kept on remote accounts). The old account then shows the
new one as `moved` in the Mastodon API. The personas following it keep
following it: following the new account on their behalf would tell another
server about them, so that waits for the owner.

Checked live against GoToSocial (scenarios/moves.sh: an alias, a move, 6
checks).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LsXgEaXee4GCU1hwYgPJXw

docs/INTEROP.md

@@ -257,6 +257,11 @@ neither the public nor the author's followers as a direct message, like our DMs,
 mentions. Being in `cc` stored it but left it invisible, so each member's copy also mentions that member silently.
 Such posts are then found in the member's conversations, never by a search on their URI.
 
+**Account moves (2026-10-05, `tools/pasture/scenarios/moves.sh`):** GoToSocial moves an account through its API (the new
+one names the old in `alsoKnownAs` first, `/api/v1/accounts/alias`) and sends `Move{object: old, target: new}` to the
+old one's followers. PrivaPub reads the new account again, finds the old one among its aliases and shows the old account
+`moved`; 6 checks pass. PrivaPub dropped `Move` as an unknown type until then.
+
 ### Misskey family: Misskey 2026.10.0, Sharkey 2025.4.7, Iceshrimp.NET 2026.1.2-beta, CherryPick 4.17
 
 Firefish is dead (its site has answered 410 since February 2025).