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/tunnelConfig.js

@@ -0,0 +1,18 @@
+// Tunnel + Tailscale shared config (all values in ms)
+export const HEALTH_CHECK = {
+  intervalMs: 2000,
+  timeoutMs: 180000,
+  fetchTimeoutMs: 5000,
+  dnsTimeoutMs: 2000,
+};
+
+export const INTERNET_CHECK = {
+  host: "1.1.1.1",
+  port: 443,
+  timeoutMs: 3000,
+};
+
+export const RESTART_COOLDOWN_MS = 60000;
+export const NETWORK_SETTLE_MS = 2500;
+export const WATCHDOG_INTERVAL_MS = 60000;
+export const NETWORK_CHECK_INTERVAL_MS = 5000;