Ref(DeviceInfo-PaymentResult-WebView):

- Refactor `PaymentResultEntity` to include a nested `PaymentResultDataEntity` and companion factory methods for success and failure.
- Update `PaymentResultStatus` enum members from `OK`/`ERROR` to `SUCCESS`/`FAILURE`.
- Modify `PspService` and its implementations (`P3`, `PS4`, `Stage`) to return a non-nullable `PaymentResultEntity`.
- Enhance `PspWebView` with improved instance lifecycle management, `rememberUpdatedState` for callbacks, and new `onWebViewReady` and `onPageFinished` hooks.
- Optimize `PspWebView` to prevent redundant `loadUrl` calls during recomposition.
- Add `README.md` and `AGENT.md` to provide project architecture overviews and hardware-specific development guidelines.
- Update `TisWebViewScreen` and `StageWebViewScreen` to handle the refactored result models and utilize new WebView callbacks.

tis_app/src/main/java/com/example/tis_app/screen/TisWebViewScreen.kt

@@ -1,5 +1,6 @@
 package com.example.tis_app.screen
 
+import android.util.Log
 import android.webkit.WebView
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
@@ -17,10 +18,10 @@ import androidx.hilt.navigation.compose.hiltViewModel
 import com.example.core.getAndroidId
 import com.example.core.getDeviceName
 import com.example.design_system.PspWebView
-import com.example.design_system.util.WebViewManager
 import com.example.tis_app.viewmodel.WebViewModel
 
 private const val tisWebUrl = "https://tis.shift-am.ir"
+private const val tisWebViewTag = "TisWebViewScreen"
 
 @Composable
 fun TisWebViewScreen(
@@ -29,10 +30,11 @@ fun TisWebViewScreen(
 ) {
 
     val context = LocalContext.current
-    var webView: WebView by remember { mutableStateOf(WebViewManager.getWebView(context)) }
+    var webView: WebView? by remember { mutableStateOf(null) }
     var currentPaymentId by rememberSaveable { mutableStateOf<String?>(null) }
     var isPaymentProcessing by rememberSaveable { mutableStateOf(false) }
     var isPrinting by rememberSaveable { mutableStateOf(false) }
+    var initialCallbackSent by rememberSaveable { mutableStateOf(false) }
     val coroutineScope = rememberCoroutineScope()
     val deviceInfo by remember {
         mutableStateOf(
@@ -50,17 +52,16 @@ fun TisWebViewScreen(
         val paymentResultEntity = viewModel.paymentResult(
             id = currentPaymentId,
             activityResult = result
-
         )
-
-        webView.post {
-            webView.evaluateJavascript(
-                viewModel.postPaymentResult(paymentResultEntity = paymentResultEntity),
-                null
-            )
+        val jsResult = viewModel.postPaymentResult(paymentResultEntity)
+        webView?.let {
+            it.post {
+                it.evaluateJavascript(jsResult, null)
+            }
+        } ?: run {
+            Log.w(tisWebViewTag, "Skipping onPaymentResult JS callback: WebView is not ready yet.")
         }
         isPaymentProcessing = false
-
     }
 
     PspWebView(
@@ -86,6 +87,15 @@ fun TisWebViewScreen(
         },
         onDeviceInfo = {
             deviceInfo
+        },
+        onWebViewReady = { readyWebView ->
+            webView = readyWebView
+        },
+        onPageFinished = { loadedWebView ->
+            if (!initialCallbackSent) {
+                loadedWebView.evaluateJavascript(viewModel.postPaymentResult(null), null)
+                initialCallbackSent = true
+            }
         }
     )
-}
+}

tis_app/src/main/java/com/example/tis_app/viewmodel/WebViewModel.kt

@@ -32,7 +32,7 @@ class WebViewModel @Inject constructor(
     fun paymentResult(
         id: String?,
         activityResult: ActivityResult
-    ): PaymentResultEntity? {
+    ): PaymentResultEntity {
         return pspService.decodePosResponse(
             id = id,
             activityResult = activityResult