feat(desktop): Gateway URL 配置化 + Rust panic hook 崩溃报告

- api-urls.ts: GATEWAY_URLS 读 VITE_GATEWAY_HTTP/WS env
- gateway-storage.ts: DEFAULT_GATEWAY_URL 读 VITE_GATEWAY_WS env
- lib.rs: 添加 tracing_subscriber 初始化 + panic::set_hook
  崩溃时自动写入 crash-reports/ 目录供诊断
- Cargo.toml: 添加 tracing-subscriber workspace 依赖

desktop/src/constants/api-urls.ts

@@ -50,8 +50,8 @@ export const LLM_PROVIDER_URLS = {
  * ZCLAW Gateway default URLs
  */
 export const GATEWAY_URLS = {
-  DEFAULT_HTTP: 'http://127.0.0.1:50051',
-  DEFAULT_WS: 'ws://127.0.0.1:50051/ws',
+  DEFAULT_HTTP: import.meta.env.VITE_GATEWAY_HTTP || 'http://127.0.0.1:50051',
+  DEFAULT_WS: import.meta.env.VITE_GATEWAY_WS || 'ws://127.0.0.1:50051/ws',
   FALLBACK_HTTP: 'http://127.0.0.1:4200',
   FALLBACK_WS: 'ws://127.0.0.1:4200/ws',
 } as const;

desktop/src/lib/gateway-storage.ts

@@ -48,7 +48,7 @@ export function isLocalhost(url: string): boolean {
 
 // ZCLAW endpoints (port 50051 - actual running port)
 // Note: REST API uses relative path to leverage Vite proxy for CORS bypass
-export const DEFAULT_GATEWAY_URL = `${DEFAULT_WS_PROTOCOL}127.0.0.1:50051/ws`;
+export const DEFAULT_GATEWAY_URL = import.meta.env.VITE_GATEWAY_WS || `${DEFAULT_WS_PROTOCOL}127.0.0.1:50051/ws`;
 export const REST_API_URL = ''; // Empty = use relative path (Vite proxy)
 export const FALLBACK_GATEWAY_URLS = [
   DEFAULT_GATEWAY_URL,