fix(ui): include error name and message in forwarded logs

WebKit (macOS WKWebView) omits the "Name: message" header from
Error.stack, so forwarding only the stack hid the real cause of
failures. Prepend the error name, message and optional cause before
the stack so daemon RPC errors surface in gui-client.log.

client/ui/frontend/src/lib/logs.ts

@@ -21,11 +21,25 @@ let inForward = false;
 let windowStart = 0;
 let windowCount = 0;
 
+// WebKit (macOS WKWebView) omits the "Name: message" header from Error.stack,
+// so a bare stack hides the real cause. Prepend name+message, then the stack.
+function formatError(e: Error): string {
+    const head = `${e.name}: ${e.message}`;
+    const rawCause = (e as { cause?: unknown }).cause;
+    const cause =
+        rawCause instanceof Error
+            ? `\ncaused by ${rawCause.name}: ${rawCause.message}`
+            : rawCause !== undefined
+              ? `\ncaused by ${String(rawCause)}`
+              : "";
+    return e.stack && !e.stack.startsWith(head) ? `${head}${cause}\n${e.stack}` : `${head}${cause}`;
+}
+
 function format(args: unknown[]): string {
     return args
         .map((a) => {
             if (typeof a === "string") return a;
-            if (a instanceof Error) return a.stack || a.message;
+            if (a instanceof Error) return formatError(a);
             try {
                 return JSON.stringify(a);
             } catch {