Following an account brings its earlier posts to its profile

Once a follow holds, OutboxBackfill reads the account's latest public posts from its outbox's first page (twenty at
most, once a day) and keeps them as any fetched post: its profile shows them at once instead of only what it posts from
then on. Homes still get only what arrives afterwards, as on Mastodon. Announces and other servers' objects in the
outbox are left out. Checked live against Mastodon (scenarios/pins.sh, now 9 checks).

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

docs/ROADMAP.md

@@ -691,7 +691,8 @@ it, raw where it doesn't.
   events, user, notification, public, hashtag and list streams, each event mapped for its persona; a deletion reaches
   only the streams that showed the post), Web Push (gated: outbound traffic to push services), grouped notifications.
   Then advertise an honest version.
-- **Backfill:** an author's outbox after following them.
+- **Backfill:** an author's outbox after following them: **done 2026-10-05** (`OutboxBackfill`, the first page's
+  public posts, twenty at most, once a day; checked live against Mastodon).
 - **Long tail:**
   - MFM rendering data;
   - Misskey actor extras;