fix(ui): keep scroll position when focusing scrolled editors (#1116)

app/src/main/java/com/m57/hermescontrol/ui/common/SyncedTextFieldState.kt

@@ -0,0 +1,50 @@
+package com.m57.hermescontrol.ui.common
+
+import androidx.compose.foundation.text.input.TextFieldState
+import androidx.compose.foundation.text.input.rememberTextFieldState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.rememberUpdatedState
+import androidx.compose.runtime.snapshotFlow
+
+/**
+ * Two-way bridge between an external [String] holder (ViewModel state, a parent
+ * callback, …) and a [TextFieldState]-backed text field.
+ *
+ * Why not `OutlinedTextField(value:, onValueChange:)`? The value-based overload
+ * keeps its selection inside the legacy `BasicTextField` implementation, so when
+ * a scrolled field gains focus it scrolls the cursor into view while the cursor
+ * is still at index 0 — the viewport jumps back to the top instead of staying
+ * where the user tapped. `TextFieldState`-backed fields only follow the cursor
+ * while the user is actively editing, so the scroll position survives the tap.
+ *
+ * Inbound (external → field) updates are applied only when the text actually
+ * differs, which keeps ViewModel round-trips from clobbering in-progress typing;
+ * outbound (field → external) updates skip the identity case so the two
+ * directions can never ping-pong.
+ */
+@Composable
+fun rememberSyncedTextFieldState(
+    value: String,
+    onValueChange: (String) -> Unit,
+): TextFieldState {
+    val state = rememberTextFieldState(value)
+    val currentValue by rememberUpdatedState(value)
+    val currentOnValueChange by rememberUpdatedState(onValueChange)
+
+    LaunchedEffect(state, value) {
+        if (state.text.toString() != value) {
+            state.edit { replace(0, length, value) }
+        }
+    }
+
+    LaunchedEffect(state) {
+        snapshotFlow { state.text.toString() }
+            .collect { newText ->
+                if (newText != currentValue) currentOnValueChange(newText)
+            }
+    }
+
+    return state
+}