🐛 fix: response body double-read regression + updater JSON safety

- hosters.js apiGet(): fixed regression from v2.3.8 where res.json()
  consumed the body, making res.text() return empty on parse failure.
  Now reads as text first, then parses JSON (matching VOE fix pattern).
- updater.js fetchJson(): same fix — read text first, parse JSON,
  show actual server response in error message on failure.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

lib/hosters.js

@@ -281,11 +281,11 @@ async function apiGet(url, signal) {
       signal: controller.signal,
       redirect: 'follow'
     });
+    const text = await res.text();
     let data;
     try {
-      data = await res.json();
+      data = JSON.parse(text);
     } catch {
-      const text = await res.text().catch(() => '');
       throw new Error(`API-Antwort war kein JSON (HTTP ${res.status}): ${(text || '').slice(0, 200)}`);
     }
 

lib/updater.js

@@ -65,7 +65,12 @@ async function fetchJson(url, signal) {
       signal: controller.signal,
       redirect: 'follow'
     });
-    return await res.json();
+    const text = await res.text();
+    try {
+      return JSON.parse(text);
+    } catch {
+      throw new Error(`Update-Server Antwort war kein JSON (HTTP ${res.status}): ${text.slice(0, 200)}`);
+    }
   } finally {
     clearTimeout(timeout);
     if (signal) signal.removeEventListener('abort', onAbort);