feat(VocabService, AppHeader): enhance timeout configuration and update ad display settings

- Updated the VocabService to allow configurable timeout for responses, defaulting to 300 seconds if not set or invalid.
- Modified AppHeader component to change ad format to horizontal and adjusted responsive settings for better display consistency.
- Ensured proper height settings for ad elements to maintain layout integrity across different screen sizes.

backend/services/vocabService.js

@@ -2844,7 +2844,11 @@ export default class VocabService {
     }
 
     const controller = new AbortController();
-    const timeout = setTimeout(() => controller.abort(), 120000);
+    const configuredTimeout = Number(process.env.LLM_ASSISTANT_TIMEOUT_MS);
+    const timeoutMs = Number.isFinite(configuredTimeout) && configuredTimeout >= 30000
+      ? configuredTimeout
+      : 300000;
+    const timeout = setTimeout(() => controller.abort(), timeoutMs);
 
     const temperatureByMode = {
       explain: 0.4,
@@ -2878,7 +2882,7 @@ export default class VocabService {
     } catch (error) {
       const err = new Error(
         error?.name === 'AbortError'
-          ? 'Der Sprachassistent hat länger als zwei Minuten für eine Antwort gebraucht.'
+          ? 'Der Sprachassistent hat das Antwort-Zeitlimit überschritten.'
           : 'Der Sprachassistent konnte nicht erreicht werden.'
       );
       err.status = 502;

frontend/src/components/AppHeader.vue

@@ -14,8 +14,8 @@
           style="display:block"
           data-ad-client="ca-pub-1104166651501135"
           :data-ad-slot="adSlotId"
-          data-ad-format="auto"
-          data-full-width-responsive="true"
+          data-ad-format="horizontal"
+          data-full-width-responsive="false"
         ></ins>
       </div>
       <div class="header-meta">
@@ -255,10 +255,25 @@ export default {
   flex: 1 1 260px;
   min-width: 180px;
   max-width: 560px;
+  min-height: 54px;
+  max-height: 54px;
+  display: flex;
+  align-items: center;
+  overflow: hidden;
 }
 
 .header-ad .adsbygoogle {
-  min-height: 54px;
+  width: 100% !important;
+  height: 54px !important;
+  min-height: 54px !important;
+  max-height: 54px !important;
+  overflow: hidden !important;
+}
+
+.header-ad :deep(iframe),
+.header-ad :deep([id^="aswift_"]) {
+  height: 54px !important;
+  max-height: 54px !important;
 }
 
 .header-meta__context {
@@ -394,6 +409,20 @@ export default {
     width: 100%;
     max-width: none;
     flex: 1 1 100%;
+    min-height: 44px;
+    max-height: 44px;
+  }
+
+  .header-ad .adsbygoogle {
+    height: 44px !important;
+    min-height: 44px !important;
+    max-height: 44px !important;
+  }
+
+  .header-ad :deep(iframe),
+  .header-ad :deep([id^="aswift_"]) {
+    height: 44px !important;
+    max-height: 44px !important;
   }
 
   .header-meta {