add few more OSes and add sub categories

app/src/main/java/sh/sar/isodroid/ui/screens/DownloadsScreen.kt

@@ -50,6 +50,7 @@ import org.json.JSONArray
 data class OsDownload(
     val name: String,
     val category: String,
+    val subcategory: String?,
     val description: String,
     val icon: String?,
     val url: String
@@ -67,6 +68,7 @@ private fun loadOsDownloads(context: Context): List<OsDownload> {
                 OsDownload(
                     name = obj.getString("name"),
                     category = obj.getString("category"),
+                    subcategory = if (obj.isNull("subcategory")) null else obj.optString("subcategory", null),
                     description = obj.optString("description", ""),
                     icon = if (obj.isNull("icon")) null else obj.optString("icon", null),
                     url = obj.getString("url")
@@ -88,11 +90,9 @@ fun DownloadsScreen(
     val context = LocalContext.current
     val downloads = remember { loadOsDownloads(context) }
 
-    // Group by category and maintain order: Linux, BSD, Windows, Recovery
-    val categoryOrder = listOf("Linux", "BSD", "Windows", "Recovery")
+    // Group by category alphabetically
     val groupedDownloads = remember(downloads) {
-        downloads.groupBy { it.category }
-            .toSortedMap(compareBy { categoryOrder.indexOf(it).takeIf { i -> i >= 0 } ?: Int.MAX_VALUE })
+        downloads.groupBy { it.category }.toSortedMap()
     }
 
     fun openUrl(url: String) {
@@ -166,22 +166,86 @@ private fun DownloadCategory(
         )
     ) {
         Column {
-            downloads.forEachIndexed { index, os ->
-                DownloadItem(
-                    os = os,
-                    onClick = { onItemClick(os) }
-                )
-                if (index < downloads.lastIndex) {
-                    HorizontalDivider(
-                        modifier = Modifier.padding(horizontal = 16.dp),
-                        color = MaterialTheme.colorScheme.outline.copy(alpha = 0.3f)
+            // Check if any items have subcategories
+            val hasSubcategories = downloads.any { it.subcategory != null }
+
+            if (hasSubcategories) {
+                // Group by subcategory alphabetically
+                val groupedBySubcategory = downloads
+                    .groupBy { it.subcategory ?: "" }
+                    .toSortedMap()
+
+                var isFirstGroup = true
+                groupedBySubcategory.forEach { (subcategory, osList) ->
+                    if (subcategory.isNotEmpty()) {
+                        // Subcategory header
+                        if (!isFirstGroup) {
+                            HorizontalDivider(
+                                modifier = Modifier.padding(horizontal = 16.dp),
+                                color = MaterialTheme.colorScheme.outline.copy(alpha = 0.3f)
+                            )
+                        }
+                        SubcategoryHeader(subcategory)
+                    }
+                    isFirstGroup = false
+
+                    osList.sortedBy { it.name.lowercase() }.forEachIndexed { index, os ->
+                        DownloadItem(
+                            os = os,
+                            onClick = { onItemClick(os) }
+                        )
+                        if (index < osList.lastIndex) {
+                            HorizontalDivider(
+                                modifier = Modifier.padding(horizontal = 16.dp),
+                                color = MaterialTheme.colorScheme.outline.copy(alpha = 0.15f)
+                            )
+                        }
+                    }
+                }
+            } else {
+                // No subcategories, show flat list
+                downloads.forEachIndexed { index, os ->
+                    DownloadItem(
+                        os = os,
+                        onClick = { onItemClick(os) }
                     )
+                    if (index < downloads.lastIndex) {
+                        HorizontalDivider(
+                            modifier = Modifier.padding(horizontal = 16.dp),
+                            color = MaterialTheme.colorScheme.outline.copy(alpha = 0.3f)
+                        )
+                    }
                 }
             }
         }
     }
 }
 
+@Composable
+private fun SubcategoryHeader(title: String) {
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 16.dp, vertical = 12.dp),
+        verticalAlignment = Alignment.CenterVertically
+    ) {
+        HorizontalDivider(
+            modifier = Modifier.weight(1f),
+            color = MaterialTheme.colorScheme.outline.copy(alpha = 0.5f)
+        )
+        Text(
+            text = title,
+            style = MaterialTheme.typography.labelMedium,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.padding(horizontal = 12.dp)
+        )
+        HorizontalDivider(
+            modifier = Modifier.weight(1f),
+            color = MaterialTheme.colorScheme.outline.copy(alpha = 0.5f)
+        )
+    }
+}
+
 @Composable
 private fun DownloadItem(
     os: OsDownload,