fix(rpc): bypass the env proxy for loopback RPC and local stats

Loopback HTTP was still subject to the process environment's proxy
settings (http_proxy / all_proxy). That routed the local daemon's
basic-auth credentials and wallet data - and the miner's 127.0.0.1
stats API - through whatever proxy the user's shell happened to
export, and could break the connection outright.

- Local daemon RPC now sets curl's no-proxy to "*" when the host is
  loopback, so it always connects directly. This also overrides a
  no_proxy list. Remote daemons keep full proxy support unchanged.
- The xmrig stats fetch against the local miner API does the same.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/daemon/xmrig_manager.cpp

@@ -739,6 +739,7 @@ void XmrigManager::fetchStatsHttp() {
     headers = curl_slist_append(headers, authHeader.c_str());
 
     curl_easy_setopt(curl, CURLOPT_URL, url);
+    curl_easy_setopt(curl, CURLOPT_NOPROXY, "*");   // 127.0.0.1 miner API: never via an env proxy
     curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
     curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curlWriteCb);
     curl_easy_setopt(curl, CURLOPT_WRITEDATA, &responseData);