feat(panel): 前端 NOT_JSON 自动回传原始响应到 /api/debug/report_bad_json（落 /tmp/overview_client_bad.txt，抓浏览器收到的真实字节）

patch_v2/meowpanel/meowpanel.c

@@ -5495,6 +5495,14 @@ static int handle(int sock, req_t *r)
         if (!strcmp(p, "/api/system/shutdown")) return api_system_action(sock, "shutdown", r);
         if (!strcmp(p, "/api/system/ota")) return api_system_action(sock, "ota", r);
         if (!strcmp(p, "/api/system/pin-unlock-once")) return api_pin_unlock_once(sock);
+        if (!strcmp(p, "/api/debug/report_bad_json")) {
+            /* 前端 NOT_JSON 自动回传浏览器收到的原始字节（抓间歇性破包） */
+            FILE *df = fopen("/tmp/overview_client_bad.txt", "w");
+            if (df && r->body && r->body_len) fwrite(r->body, 1, r->body_len, df);
+            if (df) fclose(df);
+            panel_log("debug: client bad json captured %zu bytes -> /tmp/overview_client_bad.txt", (size_t)r->body_len);
+            return send_json(sock, 200, "{\"captured\":true}");
+        }
         if (!strcmp(p, "/api/settings")) return api_settings_batch(sock, r);
         if (!strcmp(p, "/api/settings/restore")) return api_settings_restore(sock);
         if (!strcmp(p, "/api/theme")) return api_theme_put(sock, r);