feat(android): 工单列表与动作，任务页可进工单

- Api 增 tickets/ticketAction/verifyTicket/promote，状态机交给服务端，客户端只发动作
- TicketsScreen：派给我的 / 我发起的、按状态给接收/开始/提交/通过/驳回、6004 与 6003 给出人话提示
- 仍未编译验证（本机无 JDK/Gradle），见 android/README.md

android/app/src/main/java/com/dadao/task/MainActivity.kt

@@ -20,6 +20,7 @@ import com.dadao.task.ui.DadaoTheme
 import com.dadao.task.ui.HomeScreen
 import com.dadao.task.ui.LoginScreen
 import com.dadao.task.ui.TaskListScreen
+import com.dadao.task.ui.TicketsScreen
 
 class MainActivity : ComponentActivity() {
 
@@ -35,7 +36,7 @@ class MainActivity : ComponentActivity() {
     }
 }
 
-private enum class Screen { Splash, Login, Home, Tasks }
+private enum class Screen { Splash, Login, Home, Tasks, Tickets }
 
 @Composable
 private fun AppRoot() {
@@ -77,7 +78,20 @@ private fun AppRoot() {
             if (ws == null) {
                 screen = Screen.Home
             } else {
-                TaskListScreen(api = api, workspace = ws, onBack = { screen = Screen.Home })
+                TaskListScreen(
+                    api = api,
+                    workspace = ws,
+                    onBack = { screen = Screen.Home },
+                    onOpenTickets = { screen = Screen.Tickets },
+                )
+            }
+        }
+        Screen.Tickets -> {
+            val ws = current
+            if (ws == null) {
+                screen = Screen.Home
+            } else {
+                TicketsScreen(api = api, workspace = ws, onBack = { screen = Screen.Tasks })
             }
         }
     }