Refactor global styles and enhance MITM functionality

- Updated global CSS to implement a new brand color palette and improve light/dark theme consistency.
- Enhanced the MitmServerCard component to provide clearer user feedback regarding admin privileges.
- Filtered LLM combos in the CombosPage to ensure only relevant data is displayed.
- Improved APIPageClient layout for better usability and visual consistency.
- Added functionality to save and load DNS tool states in the MITM manager.
- Updated OAuth configuration URLs for Qwen to reflect the new endpoint structure.
- Refined tunnel management logic to improve reliability and user experience.

src/lib/tunnel/networkProbe.js

@@ -0,0 +1,67 @@
+import net from "net";
+import dns from "dns";
+import { INTERNET_CHECK, HEALTH_CHECK } from "./tunnelConfig.js";
+
+// Force public DNS to bypass OS negative cache (mDNSResponder holds NXDOMAIN)
+const resolver = new dns.promises.Resolver();
+resolver.setServers(["1.1.1.1", "1.0.0.1", "8.8.8.8"]);
+
+export function checkInternet() {
+  return new Promise((resolve) => {
+    const socket = new net.Socket();
+    let done = false;
+    const finish = (ok) => {
+      if (done) return;
+      done = true;
+      try { socket.destroy(); } catch { /* ignore */ }
+      resolve(ok);
+    };
+    socket.setTimeout(INTERNET_CHECK.timeoutMs);
+    socket.once("connect", () => finish(true));
+    socket.once("timeout", () => finish(false));
+    socket.once("error", () => finish(false));
+    try { socket.connect(INTERNET_CHECK.port, INTERNET_CHECK.host); }
+    catch { finish(false); }
+  });
+}
+
+async function resolveDns(hostname, timeoutMs) {
+  try {
+    await Promise.race([
+      resolver.resolve4(hostname),
+      new Promise((_, rej) => setTimeout(() => rej(new Error("dns timeout")), timeoutMs)),
+    ]);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+// Single health probe: DNS via 1.1.1.1 → fetch /api/health
+export async function probeUrlAlive(url) {
+  if (!url) return false;
+  let hostname;
+  try { hostname = new URL(url).hostname; } catch { return false; }
+
+  if (!await resolveDns(hostname, HEALTH_CHECK.dnsTimeoutMs)) return false;
+
+  try {
+    const res = await fetch(`${url}/api/health`, {
+      signal: AbortSignal.timeout(HEALTH_CHECK.fetchTimeoutMs),
+    });
+    return res.ok;
+  } catch {
+    return false;
+  }
+}
+
+// Poll until tunnel responds /api/health, or timeout. Cancellable via token.
+export async function waitForHealth(url, cancelToken = { cancelled: false }) {
+  const start = Date.now();
+  while (Date.now() - start < HEALTH_CHECK.timeoutMs) {
+    if (cancelToken.cancelled) throw new Error("cancelled");
+    if (await probeUrlAlive(url)) return true;
+    await new Promise((r) => setTimeout(r, HEALTH_CHECK.intervalMs));
+  }
+  throw new Error(`Health check timeout after ${HEALTH_CHECK.timeoutMs}ms`);
+}