Fix/Resolve panic issues in proxy-related code (#560)

* fix(proxy): change default port from 5000 to 15721

Port 5000 conflicts with AirPlay Receiver on macOS 12+.
Also adds error handling for proxy toggle and i18n placeholder updates.

* fix(proxy): replace unwrap/expect with graceful error handling

- Handle HTTP client initialization failure with no_proxy fallback
- Fix potential panic on Unicode slicing in API key preview
- Add proper error handling for response body builder
- Handle edge case where SystemTime is before UNIX_EPOCH

* fix(proxy): handle UTF-8 char boundary when truncating request body log

Rust strings are UTF-8 encoded, slicing at a fixed byte index may cut
in the middle of a multi-byte character (e.g., Chinese, emoji), causing
a panic. Use is_char_boundary() to find the nearest safe cut point.

* fix(proxy): improve robustness and prevent panics

- Add reqwest socks feature to support SOCKS proxy environments
- Fix UTF-8 safety in masked_key/masked_access_token (use chars() instead of byte slicing)
- Fix UTF-8 boundary check in usage_script HTTP response truncation
- Add defensive checks for JSON operations in proxy service
- Remove verbose debug logs that could trigger panic-prone code paths

src/components/proxy/ProxyPanel.tsx

@@ -40,7 +40,7 @@ export function ProxyPanel() {
 
   // 监听地址/端口的本地状态
   const [listenAddress, setListenAddress] = useState("127.0.0.1");
-  const [listenPort, setListenPort] = useState(5000);
+  const [listenPort, setListenPort] = useState(15721);
 
   // 同步全局配置到本地状态
   useEffect(() => {
@@ -389,7 +389,9 @@ export function ProxyPanel() {
                     id="listen-address"
                     value={listenAddress}
                     onChange={(e) => setListenAddress(e.target.value)}
-                    placeholder="127.0.0.1"
+                    placeholder={t("proxy.settings.fields.listenAddress.placeholder", {
+                      defaultValue: "127.0.0.1",
+                    })}
                   />
                   <p className="text-xs text-muted-foreground">
                     {t("proxy.settings.fields.listenAddress.description", {
@@ -410,9 +412,11 @@ export function ProxyPanel() {
                     type="number"
                     value={listenPort}
                     onChange={(e) =>
-                      setListenPort(parseInt(e.target.value) || 5000)
+                      setListenPort(parseInt(e.target.value) || 15721)
                     }
-                    placeholder="5000"
+                    placeholder={t("proxy.settings.fields.listenPort.placeholder", {
+                      defaultValue: "15721",
+                    })}
                   />
                   <p className="text-xs text-muted-foreground">
                     {t("proxy.settings.fields.listenPort.description", {

src/components/proxy/ProxyToggle.tsx

@@ -23,7 +23,11 @@ export function ProxyToggle({ className, activeApp }: ProxyToggleProps) {
     useProxyStatus();
 
   const handleToggle = async (checked: boolean) => {
-    await setTakeoverForApp({ appType: activeApp, enabled: checked });
+    try {
+      await setTakeoverForApp({ appType: activeApp, enabled: checked });
+    } catch (error) {
+      console.error("[ProxyToggle] Toggle takeover failed:", error);
+    }
   };
 
   const takeoverEnabled = takeoverStatus?.[activeApp] || false;

src/i18n/locales/en.json

@@ -1058,7 +1058,7 @@
         },
         "listenPort": {
           "label": "Listen Port",
-          "placeholder": "5000",
+          "placeholder": "15721",
           "description": "Port number the proxy server listens on (1024 ~ 65535)"
         },
         "maxRetries": {

src/i18n/locales/ja.json

@@ -1058,7 +1058,7 @@
         },
         "listenPort": {
           "label": "リッスンポート",
-          "placeholder": "5000",
+          "placeholder": "15721",
           "description": "プロキシサーバーがリッスンするポート番号（1024 ~ 65535）"
         },
         "maxRetries": {

src/i18n/locales/zh.json

@@ -1058,7 +1058,7 @@
         },
         "listenPort": {
           "label": "监听端口",
-          "placeholder": "5000",
+          "placeholder": "15721",
           "description": "代理服务器监听的端口号（1024 ~ 65535）"
         },
         "maxRetries": {