fix: 401 logout loop — sync state update, prevent re-navigation

Root cause: LoginViewModel.logout() was async (viewModelScope.launch),
so _uiState.isConnected remained true after navigating to login.
LoginScreen's LaunchedEffect immediately navigated back to dashboard,
where APIs failed with 401 again → infinite loop.

Fixes:
- SessionManager: add _invalidating flag to prevent concurrent 401 handling
- AuthInterceptor: check isSessionValid before invalidating
- LoginViewModel: update _uiState synchronously in logout(), clear token
  before launching coroutine for prefs.clear()
- LoginViewModel: call SessionManager.restoreSession() after successful login
- MainActivity: remove restoreSession() from logout handler (was incorrectly
  re-validating session right after invalidation)

Bump to v1.7.1 (versionCode 10)

android/app/build.gradle.kts

@@ -12,8 +12,8 @@ android {
         applicationId = "com.devlab.app"
         minSdk = 26
         targetSdk = 37
-        versionCode = 9
-        versionName = "1.7.0"
+        versionCode = 10
+        versionName = "1.7.1"
     }
 
     buildTypes {

android/app/src/main/java/com/devlab/app/MainActivity.kt

@@ -158,7 +158,6 @@ fun AppRoot() {
                     popUpTo(0) { inclusive = true }
                 }
                 SessionManager.consumeLogoutRequest()
-                SessionManager.restoreSession()
             }
         }
     }

android/app/src/main/java/com/devlab/app/data/api/AuthInterceptor.kt

@@ -11,7 +11,7 @@ class AuthInterceptor(private val token: String) : Interceptor {
             .build()
         val response = chain.proceed(request)
 
-        if (response.code == 401 && token.isNotBlank()) {
+        if (response.code == 401 && token.isNotBlank() && SessionManager.isSessionValid.value) {
             SessionManager.invalidateSession()
         }
 

android/app/src/main/java/com/devlab/app/data/api/SessionManager.kt

@@ -12,15 +12,20 @@ object SessionManager {
     private val _onLogoutRequest = MutableStateFlow(false)
     val onLogoutRequest: StateFlow<Boolean> = _onLogoutRequest.asStateFlow()
 
-    fun invalidateSession() {
+    private val _invalidating = MutableStateFlow(false)
+
+    fun invalidateSession(): Boolean {
+        if (_invalidating.value) return false
+        _invalidating.value = true
         _isSessionValid.value = false
         _onLogoutRequest.value = true
         RetrofitClient.setToken("")
+        return true
     }
 
     fun restoreSession() {
         _isSessionValid.value = true
-        _onLogoutRequest.value = false
+        _invalidating.value = false
     }
 
     fun consumeLogoutRequest() {

android/app/src/main/java/com/devlab/app/ui/login/LoginViewModel.kt

@@ -4,6 +4,7 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.devlab.app.ServerManagerApp
 import com.devlab.app.data.api.RetrofitClient
+import com.devlab.app.data.api.SessionManager
 import com.devlab.app.data.repository.AuthRepository
 import com.devlab.app.util.PreferencesManager
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -70,6 +71,7 @@ class LoginViewModel : ViewModel() {
                         loginResult.token, loginResult.userId,
                         loginResult.username, loginResult.email, loginResult.role
                     )
+                    SessionManager.restoreSession()
                     _uiState.value = _uiState.value.copy(
                         isLoading = false,
                         isConnected = true,
@@ -87,10 +89,10 @@ class LoginViewModel : ViewModel() {
     }
 
     fun logout() {
+        _uiState.value = LoginUiState()
+        RetrofitClient.setToken("")
         viewModelScope.launch {
             prefs.clear()
-            RetrofitClient.setToken("")
-            _uiState.value = LoginUiState()
         }
     }
 }