fix: the certificate follows CERTBOT_DOMAIN, on every pass

A pass branched on whether /etc/letsencrypt/live/<first-name> existed:
present, it ran `certbot renew`; absent, it handed over to the creation
script. Only the second path was ever told the names to ask for, so
after the first issuance CERTBOT_DOMAIN stopped reaching certbot
altogether -- renew takes the names off the certificate it already holds.
Editing the variable did nothing, silently, and the README documented the
manual issuance needed to work around it.

The branch is gone. Every pass now runs certonly with the names spelled
out, and certbot decides what that means:

  same names, not due    -> "Certificate not yet due for renewal; no
                            action taken", no connection opened, nothing
                            spent against the rate limits
  name added or removed  -> reissued with exactly the requested set
  due for renewal        -> renewed

--keep-until-expiring is what makes the first line true, and --cert-name
(already passed) is what keeps a changed list updating the existing
lineage instead of starting a second one beside it. No --expand is
needed to add a name once the lineage is named.

All three decisions were checked against the live stands: the no-op one
with a real run on testnet2, the other two as dry runs on testnet1 and
testnet2.

With the branch removed, 1-renew-cert.sh is a pass-through and the
numbering finally matches the order things run in -- 0-create-cert.sh
used to execute after 1-renew-cert.sh. So: 1-renew-cert.sh deleted,
0-create-cert.sh renamed to 1-ensure-cert.sh, which is what it now does.

Claude-Session: https://claude.ai/code/session_01BvgYcYPWd1KGABLKViVPSk

docker/scripts/entrypoint.sh

@@ -17,7 +17,7 @@
 # substitution runs in a subshell that reports the parent's jobs in bash but
 # not in dash, and bare `wait` waits for every background job in either.
 #
-# One thing this cannot fix: a signal arriving while 1-renew-cert.sh is in the
+# One thing this cannot fix: a signal arriving while 1-ensure-cert.sh is in the
 # foreground is deferred until that script returns, and an issuance talking to
 # Let's Encrypt can outlast docker's 10-second stop grace. Give the service a
 # longer `stop_grace_period` if that matters.
@@ -25,7 +25,7 @@
 trap 'exit 0' TERM INT
 
 while :; do
-  /opt/scripts/1-renew-cert.sh \
+  /opt/scripts/1-ensure-cert.sh \
     || echo "entrypoint: renewal pass failed, retrying in 12h" >&2
   sleep 12h &
   wait