Track Sieve/plan/Roundcube files and update move log

- Add financ.sieve, plan.md, roundcube.txt to version control
- Update verplaats_log.json after backup dry run
- Gitignore codex.session session file

roundcube.txt

@@ -0,0 +1,12 @@
+require ["copy","date","fileinto","regex"];
+# rule:[kwartaalmail]
+if allof (date :regex "Date" "month" "[789]", date :is "Date" "year" "2026")
+{
+	fileinto :copy "INBOX.Notes";
+}
+# rule:[zuiderzee]
+if allof (header :contains "from" "zuiderzee")
+{
+	fileinto :copy "INBOX.Notes";
+}
+