Adaptive day headers + grid column controls

Day headers:
- Dense days (>=3 photos): full header with date, count, Select/Deselect day
- Sparse days (<3 photos): small date chip overlay on first photo, no
  header row — avoids wasted space when one photo per day for a stretch

Grid column controls:
- +/- buttons in top bar change column count (2-8)
- folderScrollIndex accounts for adaptive headers and column count so
  jump-to-folder stays accurate after column changes

src/main/kotlin/com/bolenpad/photophetch/ui/BrowseScreen.kt

@@ -18,12 +18,15 @@ import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.drawWithContent
+import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ImageBitmap
 import androidx.compose.ui.graphics.toComposeImageBitmap
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
 import com.bolenpad.photophetch.model.DeviceInfo
 import com.bolenpad.photophetch.model.MediaType
 import com.bolenpad.photophetch.model.PhonePhoto
@@ -32,6 +35,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import org.jetbrains.skia.Image as SkiaImage
+import java.time.LocalDate
+import java.time.format.DateTimeFormatter
 
 @Composable
 fun BrowseScreen(state: AppState) {
@@ -41,12 +46,16 @@ fun BrowseScreen(state: AppState) {
     val config by state.config.collectAsState()
 
     Column(modifier = Modifier.fillMaxSize()) {
+        var columnCount by remember { mutableStateOf(4) }
+
         BrowseTopBar(
             deviceName = device?.displayName ?: "Browse Photos",
             selectedCount = selectedPhotos.size,
+            columnCount = columnCount,
             onBack = { state.navigateTo(Screen.CONNECT) },
             onSelectNone = { state.selectNone() },
             onImport = { state.prepareImport() },
+            onColumnChange = { columnCount = (columnCount + it).coerceIn(2, 8) },
         )
 
         if (state.shootingInHeic && !config.heicWarningDismissed) {
@@ -70,14 +79,14 @@ fun BrowseScreen(state: AppState) {
                 val scope = rememberCoroutineScope()
 
                 // Map folder name → first item index in the lazy list
-                val folderScrollIndex = remember(folderSections) {
+                val folderScrollIndex = remember(folderSections, columnCount) {
                     var idx = 0
                     folderSections.associate { (folder, byDay) ->
                         val startIdx = idx
                         idx += 1 // folder header
                         byDay.forEach { (_, dayPhotos) ->
-                            idx += 1 // day header
+                            if (dayPhotos.size >= 3) idx += 1 // day header only for dense days
-                            idx += ((dayPhotos.size + 3) / 4) // photo rows
+                            idx += ((dayPhotos.size + columnCount - 1) / columnCount) // photo rows
                         }
                         folder.name to startIdx
                     }
@@ -116,6 +125,7 @@ fun BrowseScreen(state: AppState) {
                         device = device,
                         adbBin = config.adbPath ?: "adb",
                         listState = listState,
+                        columnCount = columnCount,
                         onTogglePhoto = { state.togglePhotoSelection(it) },
                         onSelectAllFolder = { folder ->
                             folder.forEach { p ->
@@ -283,6 +293,7 @@ private fun UnifiedPhotoScroll(
     device: com.bolenpad.photophetch.model.DeviceInfo?,
     adbBin: String,
     listState: LazyListState,
+    columnCount: Int,
     onTogglePhoto: (PhonePhoto) -> Unit,
     onSelectAllFolder: (List<PhonePhoto>) -> Unit,
     onDeselectAllFolder: (List<PhonePhoto>) -> Unit,
@@ -290,6 +301,7 @@ private fun UnifiedPhotoScroll(
     modifier: Modifier = Modifier,
 ) {
 
+    // Column count — adjustable via +/- buttons in the top bar
     LazyColumn(
         state = listState,
         modifier = modifier.fillMaxSize(),
@@ -311,10 +323,14 @@ private fun UnifiedPhotoScroll(
                 )
             }
 
-            // ── Day groups ─────────────────────────────────────────────────
+            // ── Day groups — adaptive headers ──────────────────────────────
+            // Dense days (≥3 photos): full header with count + Select day button
+            // Sparse days (<3 photos): small inline date chip on first photo of the day
             section.byDay.forEach { (day, dayPhotos) ->
                 val daySelected = dayPhotos.count { it in selectedPhotos }
+                val isDense = dayPhotos.size >= 3
 
+                if (isDense) {
                     item(key = "day-${section.folder.name}-$day") {
                         DaySubHeader(
                             day = day,
@@ -323,29 +339,32 @@ private fun UnifiedPhotoScroll(
                             onSelectDay = { onSelectDay(dayPhotos) },
                         )
                     }
+                }
 
-                val rows = dayPhotos.chunked(4)
+                val rows = dayPhotos.chunked(columnCount)
                 items(
                     count = rows.size,
                     key = { idx -> "row-${section.folder.name}-$day-$idx" },
                 ) { rowIdx ->
                     val rowPhotos = rows[rowIdx]
+                    val isFirstRow = rowIdx == 0
                     Row(
-                        modifier = Modifier.fillMaxWidth()
+                        modifier = Modifier.fillMaxWidth().padding(horizontal = 8.dp),
-                            .padding(horizontal = 8.dp),
                         horizontalArrangement = Arrangement.spacedBy(3.dp),
                     ) {
-                        rowPhotos.forEach { photo ->
+                        rowPhotos.forEachIndexed { colIdx, photo ->
+                            val showDateChip = !isDense && isFirstRow && colIdx == 0
                             PhotoThumb(
                                 photo = photo,
                                 isSelected = photo in selectedPhotos,
                                 device = device,
                                 adbBin = adbBin,
                                 onToggle = { onTogglePhoto(photo) },
+                                dateChip = if (showDateChip) day else null,
                                 modifier = Modifier.weight(1f),
                             )
                         }
-                        repeat(4 - rowPhotos.size) { Spacer(Modifier.weight(1f)) }
+                        repeat(columnCount - rowPhotos.size) { Spacer(Modifier.weight(1f)) }
                     }
                     Spacer(Modifier.height(3.dp))
                 }
@@ -440,9 +459,11 @@ private fun DaySubHeader(
 private fun BrowseTopBar(
     deviceName: String,
     selectedCount: Int,
+    columnCount: Int,
     onBack: () -> Unit,
     onSelectNone: () -> Unit,
     onImport: () -> Unit,
+    onColumnChange: (Int) -> Unit,
 ) {
     TopAppBar(
         title = { Text(deviceName) },
@@ -452,6 +473,15 @@ private fun BrowseTopBar(
             }
         },
         actions = {
+            // Grid size controls
+            IconButton(onClick = { onColumnChange(-1) }, enabled = columnCount > 2) {
+                Text("−", style = MaterialTheme.typography.titleMedium)
+            }
+            Text("$columnCount", style = MaterialTheme.typography.bodySmall,
+                modifier = Modifier.padding(horizontal = 2.dp))
+            IconButton(onClick = { onColumnChange(1) }, enabled = columnCount < 8) {
+                Text("+", style = MaterialTheme.typography.titleMedium)
+            }
             if (selectedCount > 0) {
                 TextButton(onClick = onSelectNone) { Text("Clear") }
             }
@@ -501,6 +531,7 @@ private fun PhotoThumb(
     device: DeviceInfo?,
     adbBin: String,
     onToggle: () -> Unit,
+    dateChip: LocalDate? = null,
     modifier: Modifier = Modifier,
 ) {
     var thumbnail by remember(photo.devicePath) { mutableStateOf<ImageBitmap?>(null) }
@@ -565,6 +596,21 @@ private fun PhotoThumb(
             }
         }
 
+        // Sparse-day date chip — bottom left, small pill
+        if (dateChip != null) {
+            val fmt = remember { DateTimeFormatter.ofPattern("MMM d") }
+            Text(
+                fmt.format(dateChip),
+                fontSize = 10.sp,
+                color = Color.White,
+                modifier = Modifier
+                    .align(Alignment.BottomStart)
+                    .padding(4.dp)
+                    .background(Color.Black.copy(alpha = 0.5f), shape = MaterialTheme.shapes.extraSmall)
+                    .padding(horizontal = 4.dp, vertical = 1.dp),
+            )
+        }
+
         // Selection indicator top-right
         Icon(
             if (isSelected) Icons.Default.CheckCircle else Icons.Default.RadioButtonUnchecked,