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;