Follow requests asked again, and followed accounts found by name

A server can take a Follow with 202 and drop it afterwards, as Pleroma does
while it cannot fetch our actor; the request then stayed pending for good.
Following again now sends an unanswered request once more, the same
activity, at most once an hour (a delivery's `again` key).

accounts/search takes following=true: only accounts the persona follows,
by the start of their name, display name or server, never resolved; a
client fills a list with it. "already take" becomes "already taken".

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

docs/ROADMAP.md

@@ -64,7 +64,8 @@ Written 2026-10-01 from the original 2023 code, the decePubClient UI, a federati
 - [ ] P9 Reading at volume (owner decision 2026-10-04, back from "Cut"): lists, server-side filters, scheduled posts,
   followed hashtags, trends and a directory
   - [x] Lists: CRUD, members (followed accounts only, dropped when the follow ends), `timelines/list` with Mastodon's
-    replies policies, exclusive lists kept out of home. Lists are the persona's own and never federate.
+    replies policies, exclusive lists kept out of home, and `accounts/search?following=true` to fill them. Lists are the
+    persona's own and never federate.
 
 ## Intent