feat(banner): Phase 8 배너 동작을 보완한다

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

app/src/main/java/kr/co/vividnext/sodalive/v2/widget/banner/BannerView.kt

@@ -9,6 +9,10 @@ import android.view.View
 import android.widget.FrameLayout
 import android.widget.ImageView
 import android.widget.TextView
+import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle
+import androidx.lifecycle.LifecycleOwner
+import androidx.lifecycle.findViewTreeLifecycleOwner
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.LinearSmoothScroller
 import androidx.recyclerview.widget.PagerSnapHelper
@@ -37,6 +41,19 @@ class BannerView @JvmOverloads constructor(
     private val autoScrollHandler = Handler(Looper.getMainLooper())
     private val autoScrollRunnable = Runnable { moveToNextBanner() }
     private var hasWindowAttachmentForAutoScroll = false
+    private var isLifecycleStartedForAutoScroll = true
+    private var lifecycleOwner: LifecycleOwner? = null
+    private val lifecycleObserver = object : DefaultLifecycleObserver {
+        override fun onStart(owner: LifecycleOwner) {
+            isLifecycleStartedForAutoScroll = true
+            startAutoScrollIfNeeded()
+        }
+
+        override fun onStop(owner: LifecycleOwner) {
+            isLifecycleStartedForAutoScroll = false
+            stopAutoScroll()
+        }
+    }
     private val bannerScrollListener = object : RecyclerView.OnScrollListener() {
         override fun onScrollStateChanged(recyclerView: RecyclerView, newState: Int) {
             when (newState) {
@@ -66,11 +83,13 @@ class BannerView @JvmOverloads constructor(
     override fun onAttachedToWindow() {
         super.onAttachedToWindow()
         hasWindowAttachmentForAutoScroll = true
+        observeLifecycleOwner()
         startAutoScrollIfNeeded()
     }
 
     override fun onDetachedFromWindow() {
         stopAutoScroll()
+        clearLifecycleOwner()
         hasWindowAttachmentForAutoScroll = false
         super.onDetachedFromWindow()
     }
@@ -96,7 +115,7 @@ class BannerView @JvmOverloads constructor(
 
     fun setItems(items: List<BannerItem>) {
         this.items = items
-        currentIndex = BannerState.from(items.size, currentIndex).currentIndex
+        currentIndex = 0
         visibility = if (items.isEmpty()) GONE else VISIBLE
         stopAutoScroll()
         adapter.submitItems(items)
@@ -187,6 +206,7 @@ class BannerView @JvmOverloads constructor(
     private fun startAutoScrollIfNeeded() {
         stopAutoScroll()
         if (!hasWindowAttachmentForAutoScroll) return
+        if (!isLifecycleStartedForAutoScroll) return
         if (BannerState.from(items.size, currentIndex).displayMode != BannerDisplayMode.Carousel) return
         autoScrollHandler.postDelayed(autoScrollRunnable, AUTO_SCROLL_INTERVAL_MS)
     }
@@ -196,9 +216,15 @@ class BannerView @JvmOverloads constructor(
     }
 
     private fun updateCurrentIndexFromSnap() {
-        val layoutManager = requireNotNull(recyclerView).layoutManager ?: return
-        val snapView = snapHelper.findSnapView(layoutManager) ?: return
-        val position = layoutManager.getPosition(snapView)
+        val recyclerView = requireNotNull(recyclerView)
+        val layoutManager = recyclerView.layoutManager ?: return
+        val snapView = snapHelper.findSnapView(layoutManager)
+        val snapPosition = snapView?.let(layoutManager::getPosition) ?: RecyclerView.NO_POSITION
+        val position = if (snapPosition == RecyclerView.NO_POSITION) {
+            currentAdapterPosition
+        } else {
+            snapPosition
+        }
         currentAdapterPosition = position
         currentIndex = adapter.toRealIndex(position)
         updateCounter()
@@ -213,10 +239,25 @@ class BannerView @JvmOverloads constructor(
         val formatted = BannerCounterFormatter.format(state.currentIndex, items.size)
         val parts = formatted.split(" ")
         currentIndexText?.text = parts[0]
-        separatorText?.text = parts[1]
+        separatorText?.text = " ${parts[1]} "
         totalCountText?.text = parts[2]
     }
 
+    private fun observeLifecycleOwner() {
+        val owner = findViewTreeLifecycleOwner() ?: return
+        if (lifecycleOwner === owner) return
+        clearLifecycleOwner()
+        lifecycleOwner = owner
+        isLifecycleStartedForAutoScroll = owner.lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED)
+        owner.lifecycle.addObserver(lifecycleObserver)
+    }
+
+    private fun clearLifecycleOwner() {
+        lifecycleOwner?.lifecycle?.removeObserver(lifecycleObserver)
+        lifecycleOwner = null
+        isLifecycleStartedForAutoScroll = true
+    }
+
     private fun Int.dpToPx(): Int = (this * resources.displayMetrics.density).roundToInt()
 
     companion object {

app/src/main/res/layout/view_banner.xml

@@ -33,7 +33,7 @@
 
         <TextView
             android:id="@+id/tv_banner_current_index"
-            style="@style/Typography.Caption2"
+            style="@style/Typography.Body5"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:textColor="@color/white"
@@ -41,7 +41,7 @@
 
         <TextView
             android:id="@+id/tv_banner_counter_separator"
-            style="@style/Typography.Caption2"
+            style="@style/Typography.Body5"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:textColor="@color/gray_400"
@@ -49,7 +49,7 @@
 
         <TextView
             android:id="@+id/tv_banner_total_count"
-            style="@style/Typography.Caption2"
+            style="@style/Typography.Body5"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:textColor="@color/gray_400"