Compat: run them from a copy, and keep our listeners out of the way

Rehearsed the run against a real RocksDB store, and it died at startup
before checking anything: the harness inserts listeners of its own, the
registry keys them by name, and a real server already has a "jmap" and an
"imap". The message was "Primary key conflict on property name with
existing object NetworkListener", which says nothing about what to do.
Under NO_INSERT the harness now calls its listeners compat-jmap and so on,
and the same run gets through to the test's own checks.

run-compat.sh copies the store for each test and removes the copy after,
because several of these write to what they open: monitoring_compat purges
the history it reads and undelete_compat restores what it finds. The source
stays untouched, which matters when it is the only copy of a production
store anyone took that day.

INBUXA runs RocksDB, so a copy is a directory copy. The SQL backends would
need more than this: the harness builds its own container and connects to
fixed local credentials, so it cannot open a dump in place.

tools/fork/README.md

@@ -32,3 +32,13 @@ tools/fork/record-compat.py --server https://mail.example.org \
     --admin '[email protected]:PASSWORD' --out ./compat \
     --tenant-admin '[email protected]:PASSWORD'
 ```
+
+## run-compat.sh
+
+Runs the `*_compat` tests against a copy of INBUXA's RocksDB store, making
+a fresh copy for each one. See `docs/spec/compat-tests.md`.
+
+```bash
+tools/fork/run-compat.sh --store /srv/inbuxa-copy/rocks.db \
+    --admin '[email protected]:PASSWORD' --recordings ~/compat
+```