Own server tags in the web panel (Settings) and server.json

Tags (max. 6, normalized like the keymaster) are sent with the heartbeat;
official and featured are only given by the MSCO admins and are refused with
a note. MSCO_TAGS environment variable.

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

Panel/app.js

@@ -396,6 +396,8 @@ function renderSettings(page) {
         h("div", { class: "section-body form-grid wide" },
           text("name", "Server name", c.name, { max: 60 }),
           text("description", "Description", c.description, { max: 300 }),
+          text("tags", "Tags", c.tags, { max: 140, placeholder: "e.g. german, roleplay, vanilla",
+            hint: "Shown in the server list, comma separated (max. 6). The tag official is only given by the MSCO admins." }),
           number("maxPlayers", "Max players", c.maxPlayers, { min: 1, max: 64 }),
           text("publicAddress", "Public address", c.publicAddress, { max: 200, placeholder: "automatic", hint: "IP or domain players connect to (empty = automatic)" }),
           toggle("isPublic", "Listed in the server browser", c.isPublic),