Personas prove what goes to relays; the server says what it reads

FEP-521a and FEP-8b32. Every persona has an Ed25519 key of its own (Avatar.SigningKey; migration 014 gives the earlier
ones theirs), named in its actor's assertionMethod as a Multikey, the terms defined in the actor's own context. A
persona's activity going to a relay carries an eddsa-jcs-2022 proof (JSON canonicalised by RFC 8785, Jcs), so what
Activity-Relay forwards reaches Mastodon, which verifies it with its own code. Nothing else carries one: Mitra takes a
proof over the HTTP signature and refuses one by a key it has not read, without reading the actor again. Received: an
actor's own Multikeys are kept, and a forwarded activity whose proof one of them verifies is taken as it came instead of
being read again from its origin.

Discovery: WebFinger for the server's origin links its instance actor (FEP-d556), NodeInfo links it as the application
actor (FEP-2677), and actors name RFC 9421 under implements (FEP-844e).

Checked live: relay 16 (Activity-Relay's forward of alice's post reaches Mastodon), Mitra, GoToSocial and Mastodon
unchanged (165 in all).

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

tools/pasture/scenarios/relay.sh

@@ -1,7 +1,8 @@
 # Relays as PrivaPub uses them (Federation:Relays in appsettings.Pasture.json): Activity-Relay, which forwards what its
 # subscribers send, and aode-relay, which announces it. For each, the instance actor subscribes, Mastodon subscribes too,
 # a public post of a Mastodon account nobody here follows reaches PrivaPub's federated timeline through the relay, and a
-# persona's public post goes to the relay (owner decision 2026-10-06), nothing less public. Mastodon leaves each relay
+# persona's public post goes to the relay (owner decision 2026-10-06), nothing less public, and reaches Mastodon through
+# it: forwarded on its FEP-8b32 proof, or announced. Mastodon leaves each relay
 # after, so the town sees no relayed posts. Needs the relay, aoderelay and mastodon peers.
 M=https://mastodon.test:6443
 mcurl() { curl -sk --resolve mastodon.test:6443:127.0.0.1 "$@"; }
@@ -38,10 +39,16 @@ until_true 60 'p_public_has "$s_uri"' && ok "a public post of an account nobody
 	&& ok "and no one's home" || ko "the relayed post landed in alice's home"
 # relay_creates <text>: the Creates PrivaPub has queued for relay.test naming the text
 relay_creates() { podman exec pasture-mongo mongosh --quiet PrivaPub --eval 'print(db.Job.countDocuments({Host:"relay.test", Payload:/Create/, Payload:/'"$1"'/}))'; }
-curl -s -o /dev/null -X POST -H "$PH" "$P/api/v1/statuses" -d "status=a PrivaPub post for the relay $run&visibility=public"
+# (Mastodon reads a known account's keys again at most daily: made to read alice's anew, with her Ed25519 key)
+alice_uri="$(curl -s -H "$PH" "$P/api/v1/accounts/verify_credentials" | j "print(d['url'])" | sed 's|/@|/peasants/|')"
+podman exec pasture-mastodon bin/rails runner "Account.where(uri: \"$alice_uri\").update_all(last_webfingered_at: nil)" >/dev/null 2>&1
+r_post=$(curl -s -X POST -H "$PH" "$P/api/v1/statuses" -d "status=a PrivaPub post for the relay $run&visibility=public" | j "print(d['uri'])")
 curl -s -o /dev/null -X POST -H "$PH" "$P/api/v1/statuses" -d "status=a quiet PrivaPub post $run&visibility=unlisted"
 until_true 30 '[ "$(relay_creates "a PrivaPub post for the relay $run")" = "1" ]' && ok "alice's public post goes to the relay" || ko "PrivaPub never sent the relay alice's public post"
 [ "$(relay_creates "a quiet PrivaPub post $run")" = "0" ] && ok "and nothing less public" || ko "PrivaPub sent the relay an unlisted post"
+# Activity-Relay forwards her Create as she sent it, signed by the relay: Mastodon takes it on its FEP-8b32 proof
+until_true 60 '[ "$(podman exec pasture-mastodon bin/rails runner "puts Status.exists?(uri: \"$r_post\")" 2>/dev/null | tail -1)" = "true" ]' \
+	&& ok "alice's public post reaches Mastodon through Activity-Relay, on its proof" || ko "Mastodon dropped alice's post forwarded by Activity-Relay"
 
 m_unrelay relay.test
 until_true 45 '! relay_subscribers | grep -qx mastodon.test' && ok "Mastodon leaves Activity-Relay" || ko "Mastodon is still subscribed to Activity-Relay"