docs: add detailed 32960 pipeline comments

modules/apps/command-gateway/src/main/java/com/lingniu/ingest/gateway/CommandGatewayAutoConfiguration.java

@@ -11,4 +11,5 @@ import org.springframework.web.servlet.DispatcherServlet;
 @ConditionalOnProperty(prefix = "lingniu.ingest.command-gateway", name = "enabled", havingValue = "true", matchIfMissing = true)
 @ComponentScan(basePackageClasses = TerminalCommandController.class)
 public class CommandGatewayAutoConfiguration {
+    // 只扫描 REST 下行命令网关；不参与 32960 接收、RAW 冷存或历史查询链路。
 }

modules/apps/command-gateway/src/main/java/com/lingniu/ingest/gateway/TerminalCommandController.java

@@ -205,12 +205,14 @@ public class TerminalCommandController {
     // ===== helpers =====
 
     private Optional<DeviceSession> resolveSession(String clientId) {
+        // 运维侧常拿到 VIN、手机号或 sessionId 中任意一个；这里按三索引兜底解析到在线连接。
         return sessions.findBySessionId(clientId)
                 .or(() -> sessions.findByPhone(clientId))
                 .or(() -> sessions.findByVin(clientId));
     }
 
     private CommandResult awaitSync(String clientId, Jt808Commands.DownlinkCommand cmd, String op) {
+        // 需要终端应答的命令走 request-response，超时时间由网关统一兜底，避免 HTTP 线程无限等待。
         CompletableFuture<Jt808Message> future =
                 dispatcher.request(clientId, cmd, Jt808Message.class, DEFAULT_TIMEOUT);
         try {
@@ -229,6 +231,7 @@ public class TerminalCommandController {
 
     private CommandResult fireAndForget(String clientId, Jt808Commands.DownlinkCommand cmd, String op) {
         try {
+            // ACK 类命令不等待终端回包；只确认写入在线 session 对应的 channel。
             dispatcher.notify(clientId, cmd).join();
             return CommandResult.ok(Map.of("op", op));
         } catch (Exception e) {