Add radio now-playing metadata polling and readonly props

client/public/version.js

@@ -1,5 +1,5 @@
 // Maintainer-controlled web client version.
 // Format: YYYY.MM.DD Rn (example: 2026.02.20 R2)
-window.CHGRID_WEB_VERSION = "2026.02.25 R257";
+window.CHGRID_WEB_VERSION = "2026.02.25 R258";
 // Optional display timezone for timestamps. Falls back to America/Detroit if unset/invalid.
 window.CHGRID_TIME_ZONE = "America/Detroit";

client/src/items/itemRegistry.ts

@@ -308,6 +308,12 @@ export function isItemPropertyVisible(item: WorldItem, key: string): boolean {
     const actual =
       item.params[conditionKey] ??
       getItemTypeGlobalProperties(item.type)[conditionKey];
+    if (typeof expected === 'string' && expected.startsWith('!')) {
+      if (String(actual) === expected.slice(1)) {
+        return false;
+      }
+      continue;
+    }
     if (actual !== expected) {
       return false;
     }