feature: add TimedVisibility composable for delayed content display

app/src/main/java/hu/bbara/purefin/common/ui/components/TimedVisibility.kt

@@ -0,0 +1,39 @@
+package hu.bbara.purefin.common.ui.components
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import kotlinx.coroutines.delay
+
+/**
+ * A composable that displays content for a specified duration after the value becomes null.
+ *
+ * @param value The value to display. When set to a non-null value, it will be shown immediately.
+ *              When set to null, the previously shown value will remain visible for [hideAfterMillis]
+ *              before being hidden.
+ * @param hideAfterMillis The duration in milliseconds to keep showing the last value after [value] becomes null.
+ *                        Defaults to 1000ms (1 second).
+ * @param content The composable content to display, receiving the current non-null value.
+ */
+@Composable
+fun TimedVisibility(
+    value: Long?,
+    hideAfterMillis: Long = 1_000,
+    content: @Composable (Long) -> Unit,
+) {
+    val shownValue = remember { mutableStateOf<Long?>(null) }
+
+    LaunchedEffect(value) {
+        if (value == null) {
+            delay(hideAfterMillis)
+            shownValue.value = null
+        }
+        shownValue.value = value
+    }
+
+    shownValue.value?.let {
+        content(it)
+    }
+}