fix(logs): the browser's copy of a polled read is quiet too

The server now logs polled reads at DEBUG, and the browser's copy of each
request line promises the server's level: at INFO the unread-count polls
filled My log within minutes and, at Detailed, the shipped log. The server
marks a line it logged at DEBUG with X-Log-Quiet, so the polled-route list
stays in one place.

frontend/src/lib/api/core.ts

@@ -7,7 +7,7 @@ import i18n from "../../i18n";
 import { formatBytes } from "../format";
 import { reportError } from "../errorDialog";
 import { activeAccountId, pinActiveAccount } from "../activeAccount";
-import { logRequest, REQUEST_ID_HEADER, ROUTE_HEADER, send } from "../http";
+import { logRequest, QUIET_HEADER, REQUEST_ID_HEADER, ROUTE_HEADER, send } from "../http";
 import { newRequestId } from "../log";
 
 /** The active UI language, as a bare code the server understands ("en"/"hu" — never "en-GB").
@@ -374,6 +374,7 @@ export function uploadReq<T = unknown>(
         status: xhr.status,
         // Test doubles may not implement it; a real XHR always does.
         route: xhr.getResponseHeader?.(ROUTE_HEADER),
+        quiet: xhr.getResponseHeader?.(QUIET_HEADER) === "1",
       });
       if (!RETRIABLE_GATEWAY.has(xhr.status)) markConnectivityRestored(); // as in `req`
       if (xhr.status >= 200 && xhr.status < 300) {