fix(remote-desktop): stop unsolicited clipboard read prompts (#1482)

* fix(remote-desktop): read clipboard only on explicit paste

* test(css): exercise the configured PostCSS plugin chain

* test(identity): preserve full Ed25519 public keys in fixtures

* test(remote-desktop): always mutate ciphertext in tamper test

plugins/remote-desktop/src/frontend/GuacamoleDisplay.tsx

@@ -815,28 +815,6 @@ export const GuacamoleDisplay = forwardRef<
     rescaleDisplay,
   ]);
 
-  const syncClipboard = useCallback(() => {
-    const client = clientRef.current;
-    if (!client || !navigator.clipboard?.readText) return;
-    navigator.clipboard
-      .readText()
-      .then((text) => {
-        if (text) {
-          const stream = client.createClipboardStream("text/plain");
-          const writer = new Guacamole.StringWriter(stream);
-          writer.sendText(text);
-          writer.sendEnd();
-        }
-      })
-      .catch(() => {});
-  }, []);
-
-  useEffect(() => {
-    if (isVisible && isReady) {
-      syncClipboard();
-    }
-  }, [isVisible, isReady, syncClipboard]);
-
   useEffect(() => {
     const container = containerRef.current;
     const protocol = connectionConfig.protocol ?? connectionConfig.type;
@@ -882,18 +860,6 @@ export const GuacamoleDisplay = forwardRef<
     };
   }, [applyZoom, connectionConfig.protocol, connectionConfig.type, isReady]);
 
-  useEffect(() => {
-    const container = containerRef.current;
-    if (!container || !isReady) return;
-
-    const handleFocus = () => syncClipboard();
-    container.addEventListener("mouseenter", handleFocus);
-
-    return () => {
-      container.removeEventListener("mouseenter", handleFocus);
-    };
-  }, [isReady, syncClipboard]);
-
   const canDropFiles = allowUpload && onDropFiles != null;
   const [isDraggingFiles, setIsDraggingFiles] = useState(false);
   // Nested elements fire dragleave as the pointer crosses them, so track depth