fix: add app shutdown cleanup for port forward processes

- Add shutdown_port_forwards() Rust command to kill all child processes
- Add shutdownPortForwardsCmd() frontend command wrapper
- Add cleanup effect in App.tsx to call shutdown on unmount
- All port forward child processes now killed on app exit

src/App.tsx

@@ -1,4 +1,4 @@
-import React, { useState, useEffect } from "react";
+import React, { useState, useEffect, useRef } from "react";
 import { Routes, Route, NavLink, useLocation } from "react-router-dom";
 import {
   Home,
@@ -17,7 +17,7 @@ import {
   FileCode,
 } from "lucide-react";
 import { useSettingsStore } from "@/stores/settingsStore";
-import { getAppVersionCmd, loadAiProvidersCmd, testProviderConnectionCmd } from "@/lib/tauriCommands";
+import { getAppVersionCmd, loadAiProvidersCmd, testProviderConnectionCmd, shutdownPortForwardsCmd } from "@/lib/tauriCommands";
 
 import Dashboard from "@/pages/Dashboard";
 import NewIssue from "@/pages/NewIssue";
@@ -56,12 +56,25 @@ export default function App() {
   const [collapsed, setCollapsed] = useState(false);
   const [appVersion, setAppVersion] = useState("");
   const { theme, setTheme, setProviders, getActiveProvider } = useSettingsStore();
+  const cleanupDone = useRef(false);
   void useLocation();
 
   useEffect(() => {
     getAppVersionCmd().then(setAppVersion).catch(() => {});
   }, []);
 
+  // Cleanup port forwards on app unmount
+  useEffect(() => {
+    return () => {
+      if (!cleanupDone.current) {
+        cleanupDone.current = true;
+        void shutdownPortForwardsCmd().catch((err) => {
+          console.error("Failed to shutdown port forwards:", err);
+        });
+      }
+    };
+  }, []);
+
   // Load providers and auto-test active provider on startup
   useEffect(() => {
     const initializeProviders = async () => {

src/lib/tauriCommands.ts

@@ -788,3 +788,6 @@ export const deletePortForwardCmd = (id: string) =>
 
 export const listPortForwardsCmd = () =>
   invoke<PortForwardResponse[]>("list_port_forwards");
+
+export const shutdownPortForwardsCmd = () =>
+  invoke<void>("shutdown_port_forwards");