Have ipx add, rm and import tell a running daemon to read the catalogue again (#120)

`docker exec iPX ipx rm make` printed "removed make" and took it out of the catalogue table, but
the web UI went on listing it. add, rm and import run in a process of their own and write the
whole catalogue there; the daemon kept its own copy in memory, and its next change of its own --
an admin's edit, a feed categorised (#117), a moved feed followed (#115) -- wrote the removed
feed back and dropped any the command line had added.

A new socket command, reload, has the daemon read the catalogue and settings again from the
database. The socket answers it at once, as it answers status, with the counts after it: queued
behind a scan, the web UI could write the old copy back in the meantime. add, rm and import send
it when a daemon is live, and say so if it does not answer. User commands need nothing: the
daemon reads accounts from the database on every request.

A browser test runs the real `ipx add --list` and `ipx rm` against the test daemon, with an
admin's edit after each, and fails without this.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - A feed whose address answers with nothing, as a lapsed domain does behind a DNS filter's block page, shows as failing, with what to do about it, instead of as a show that has not posted yet.
 - The search box finds episodes in Currently Listening. It did nothing there.
+- `ipx add`, `ipx rm` and `ipx import`, run while the daemon runs, reach it at once. It kept its old list of feeds and wrote it back at its next change, undoing them.
 - On Postgres, a write no longer waits for the database server's disk. A scan read about one feed a second and now reads 1,500 in 20 seconds.
 - Checking every feed no longer makes every icon in the feed list flash while it runs: the list keeps the icons it has already drawn.