fix the issue

frontend/src/App.tsx

@@ -52,13 +52,20 @@ function App() {
   const canRedo = hist.index < hist.stack.length - 1;
   const preservePageRef = useRef(false);
 
+  const [isOcrDisabled, setIsOcrDisabled] = useState(false);
   const permissions = activeDoc?.permissions ?? null;
   const can = (flag: keyof PDFPermissions) => !permissions || permissions[flag] !== false;
   const denyToast = (_label: string) => { };
   const disabledTools = new Set<ToolId>();
-  if (!can('canAnnotate'))
-    (['highlight', 'underline', 'strikeout', 'squiggly', 'draw', 'comment', 'textbox', 'stamp', 'signature'] as ToolId[]).forEach((t) => disabledTools.add(t));
-  if (!can('canModify')) (['edit_text', 'redact'] as ToolId[]).forEach((t) => disabledTools.add(t));
+  disabledTools.add('ocr'); // OCR & Edit button is permanently disabled
+  if (!activeDoc) {
+    (['highlight', 'underline', 'strikeout', 'squiggly', 'draw', 'comment', 'textbox', 'edit_text', 'stream_edit', 'signature', 'stamp', 'watermark', 'redact'] as ToolId[]).forEach((t) => disabledTools.add(t));
+  } else {
+    if (!can('canAnnotate'))
+      (['highlight', 'underline', 'strikeout', 'squiggly', 'draw', 'comment', 'textbox', 'stamp', 'signature'] as ToolId[]).forEach((t) => disabledTools.add(t));
+    if (!can('canModify'))
+      (['edit_text', 'stream_edit', 'redact'] as ToolId[]).forEach((t) => disabledTools.add(t));
+  }
   const disabledToolsRef = useRef(disabledTools);
   disabledToolsRef.current = disabledTools;
 
@@ -153,7 +160,11 @@ function App() {
       await gatewayService.performPageOCR(activeDoc.id, currentPage);
       viewerRef.current?.refreshPageLayout(currentPage);
     } catch (err: any) {
-      alert(`OCR processing failed: ${err.message || err}`);
+      const errMsg = err.message || String(err);
+      alert(`OCR processing failed: ${errMsg}`);
+      if (errMsg.toLowerCase().includes('not installed') || errMsg.toLowerCase().includes('not available')) {
+        setIsOcrDisabled(true);
+      }
     } finally {
       setIsOCRLoading(false);
     }

frontend/src/lib/gatewayService.ts

@@ -727,7 +727,9 @@ class GatewayService {
       method: 'POST',
     });
     if (!response.ok) {
-      throw new Error(`OCR failed: ${response.statusText}`);
+      const errJson = await response.json().catch(() => null);
+      const detail = errJson?.detail || response.statusText;
+      throw new Error(detail);
     }
     return response.json();
   }