fix(backfill-timeline): exclude unlisted posts from ap_timeline on startup

backfillTimeline() runs on every Indiekit restart and backfills ap_timeline
from the posts collection. The query had no visibility filter, so unlisted
posts (e.g. Swarm checkins) were inserted into ap_timeline and became visible
in Mastodon API timelines (Phanpy/Elk).

Root cause traced via ObjectId timestamp: bc625 ap_timeline entry was created
at restart time (20:56 UTC), not via the syndicator (which already had an
unlisted guard). The backfill ran on startup and inserted the post.

Fix: add 'properties.visibility': { $ne: 'unlisted' } to the posts.find()
query in backfill-timeline.js. Also deleted 18 existing unlisted posts from
ap_timeline (cleanup applied directly on server).

scripts/patch-federation-unlisted-guards.mjs

@@ -2,13 +2,39 @@ import { access, readFile, writeFile } from "node:fs/promises";
 
 // activitypub index.js and federation-setup.js unlisted guards are now
 // built into the fork — only endpoint-syndicate (separate package) needs patching.
+// backfill-timeline.js also needs patching — it runs on every startup and
+// backfills ap_timeline from posts without filtering unlisted posts.
 
 const endpointSyndicateCandidates = [
   "node_modules/@indiekit/endpoint-syndicate/lib/utils.js",
   "node_modules/@indiekit/indiekit/node_modules/@indiekit/endpoint-syndicate/lib/utils.js",
 ];
 
+const backfillTimelineCandidates = [
+  "node_modules/@rmdes/indiekit-endpoint-activitypub/lib/mastodon/backfill-timeline.js",
+];
+
 const patchSpecs = [
+  {
+    name: "backfill-timeline-unlisted-guard",
+    candidates: backfillTimelineCandidates,
+    oldSnippet: `  const allPosts = await posts
+    .find({
+      "properties.post-status": { $ne: "draft" },
+      "properties.deleted": { $exists: false },
+      "properties.url": { $exists: true },
+    })
+    .toArray();`,
+    newSnippet: `  const allPosts = await posts
+    .find({
+      "properties.post-status": { $ne: "draft" },
+      "properties.deleted": { $exists: false },
+      "properties.url": { $exists: true },
+      // Exclude unlisted posts — they must not appear in ap_timeline (Mastodon API).
+      "properties.visibility": { $ne: "unlisted" },
+    })
+    .toArray();`,
+  },
   {
     name: "endpoint-syndicate-source-url-unlisted-guard",
     candidates: endpointSyndicateCandidates,