Pasture: Mitra 5.9.1

Mitra joins the pasture (peers/mitra.sh) on the shared Postgres; scenarios/mitra.sh drives its Mastodon API through
follows, posts, replies, likes, reposts, a reaction, a poll, edits, deletions, direct messages, the unfollow and
statistics: 28 checks, with no change to PrivaPub. Mitra carries FEP-8b32 proofs made with Ed25519, which PrivaPub does
not verify yet.

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

docs/INTEROP.md

@@ -753,6 +753,17 @@ PeerTube's own instance account announces each new video too, which we drop: nob
 follow only PeerTube-like channels and accounts, never a persona. It checks the `Host` header against its own name,
 without a port, before it gives out its OAuth client.
 
+### Mitra 5.9.1
+
+- Signs its deliveries with RSA (draft-cavage) and adds an FEP-8b32 proof made with its Ed25519 key (FEP-521a), which
+  PrivaPub does not verify yet; the HTTP signature is enough for what it delivers itself.
+- Its Mastodon API resolves an account elsewhere only when the search is not limited to a type
+  (`/api/v2/search?resolve=true`, no `type=accounts`); reactions go through Pleroma's route
+  (`PUT /api/v1/pleroma/statuses/:id/reactions/:emoji`).
+- **Pasture evidence (2026-10-05, `tools/pasture/scenarios/mitra.sh`):** 28 checks pass, with no change to PrivaPub:
+  follows both ways, posts, replies both ways, likes and reposts both ways, an emoji reaction, a poll and alice's vote,
+  edits and deletions both ways, direct messages both ways, the unfollow, statistics.
+
 ### Relays: Activity-Relay 2.0.9 and aode-relay 0.3.129
 
 - **Activity-Relay** takes a subscription as a `Follow` of `Public` from an actor with a shared inbox (Mastodon's way)