test(fls): e-mail account files against Swift's reader

The Swift oracle reads the 43 account files Java read (--email-files, with
TopologyRuntimeEmailStorage.decodeJavaServer and decodeJavaClient). The
accounts the model takes match Swift's except where Swift checks names,
hosts and addresses and fails the whole file on one it rejects, or reads
the format otherwise (the first client line instead of the last, exactly
nine fields, a required messages field). Every departure is named with its
reason; Java's reading is right in each, none is a Java error Swift fixes.

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

tools/swift-oracle/README.md

@@ -38,6 +38,10 @@ Sortierung, Base64 — und die ganzen Mengen `whitespacesAndNewlines` und
 unter Linux; ihre Steuerzeichen-Tabelle hat in Ebene 14 einen Fehler, den
 der Port nicht übernimmt.
 
+`--email-files server|client` liest die Kontodateien
+(`packages/fls/test/email-*.cases.txt`) mit Swifts
+`TopologyRuntimeEmailStorage.decodeJavaServer`/`decodeJavaClient`.
+
 `--dns-hosts` liest dieselben `/dns/hosts`-Fälle wie das Java-Orakel
 (`packages/fls/test/dns-hosts.cases.txt`) mit Swifts
 `TopologyDNSHostsFileCodec`; unter `state` stehen die DNS-Einträge jedes