Pasture: Lemmy 0.19 joins, built to trust the pasture's CA

Most of the threadiverse runs Lemmy 0.19, whose release trusts only the
roots its rustls bundles. images/lemmy19 builds 0.19.20 from its tag with
reqwest's rustls-tls-native-roots added, and the pasture runs it as
lemmy19.test. scenarios/lemmy19.sh passes 27 checks with no change to
PrivaPub (communities, threads, comments, votes, its private message,
moderation) and one known gap: 0.19 takes private messages only as
ChatMessage and answers our direct Note 400, like Mbin, so G-0008 now
covers both and waits for the owner.

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

docs/INTEROP.md

@@ -554,7 +554,15 @@ What it showed:
   minute after the server is first seen, at the newest activity and skips everything older. On a clean pasture its
   first Follow of our community was lost, so the scenario waits for the worker (`federation_queue_state`). On the
   public network the same applies to the first thing a Lemmy sends to a PrivaPub it has just discovered.
-- 0.19 cannot join the pasture: its rustls trusts only its bundled roots, never Caddy's CA.
+- 0.19's release trusts only the roots its rustls bundles, never Caddy's CA, so the pasture builds 0.19.20 from its tag
+  with reqwest's `rustls-tls-native-roots` added (`tools/pasture/images/lemmy19`) and runs it as `lemmy19.test`.
+- **0.19 takes private messages only as `ChatMessage`** (`ChatMessageType` has no `Note`) and answers our direct
+  `Note` 400. Most of the threadiverse runs 0.19, so this matters more than Mbin's same rule (G-0008).
+- **Pasture evidence (2026-10-05, Lemmy 0.19.20, `tools/pasture/scenarios/lemmy19.sh`):** 27 checks pass and one gap is
+  expected (G-0008, direct messages to it), with no change to PrivaPub: communities both ways, threads with titles,
+  comments both ways, votes up and down both ways (relayed in the community's announces, as 1.0 does), its private
+  message to alice, a moderator's lock (replies then refused), unlock, ban and unban (`blocked_by`) and removal,
+  statistics.
 
 ### PieFed 1.7.17 and Mbin 1.10.1