docs/hub: update Element Calling port guidance to the new port set

User-facing polish to match the element-calling port changes:

- helpers.js: port-forward guide example now shows the 40000-40099 range
  instead of the removed 30000-40000.
- versions.json: livekit dev fallback 1.5.2 -> 1.13.6 (the Nix-generated
  version in sovran-hub.nix already derives from pkgs.livekit.version).
- server.py: docstring/comment examples reference 40000-40099.
- CHANGELOG.md: record the calling changes under [Unreleased].

The tile/modal port tables themselves are data-driven from server.py's
port_requirements / _PORTS_ELEMENT_CALLING (updated in the previous commit),
so no further UI changes are needed.

app/sovran_systemsos_web/static/js/helpers.js

@@ -88,7 +88,7 @@ function renderPortForwardGuideHtml(ports, opts) {
     '<ul class="port-req-steps">' +
       '<li>Set the <strong>internal (private) port</strong> and the <strong>external (public) port</strong> to the <strong>same number</strong>.</li>' +
       '<li>Match the <strong>protocol</strong> exactly — a rule set to TCP will not pass UDP traffic. Where the table says <strong>TCP + UDP</strong>, create both rules (or pick &ldquo;Both&rdquo;/&ldquo;TCP/UDP&rdquo; if your router offers it).</li>' +
-      '<li>For a range such as <strong>30000-40000</strong>, use your router&rsquo;s port-range fields — start 30000, end 40000 — rather than one rule per port.</li>' +
+      '<li>For a range such as <strong>40000-40099</strong>, use your router&rsquo;s port-range fields — start 40000, end 40099 — rather than one rule per port.</li>' +
     '</ul>' +
     '<table class="' + tableClass + '">' +
       '<thead><tr><th>Port(s)</th><th>Protocol</th><th>Used for</th></tr></thead>' +