M3: extension manager screen (list, enable/disable)

app/src/main/java/dev/nova/browser/ExtensionManagerScreen.kt

@@ -0,0 +1,99 @@
+package dev.nova.browser
+
+import androidx.compose.foundation.layout.*
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.*
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+
+/**
+ * M3 extension manager: lists installed WebExtensions (from
+ * WebExtensionController.list()) with name/version/description and an
+ * enable/disable switch per add-on.
+ */
+@Composable
+fun ExtensionManagerScreen(
+    extensions: List<TabManager.ExtInfo>,
+    enabledStates: Map<String, Boolean>,
+    loading: Boolean,
+    onToggle: (String, Boolean) -> Unit,
+    onDismiss: () -> Unit,
+) {
+    Surface(modifier = Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.surface) {
+        Column(Modifier.fillMaxSize().padding(12.dp)) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Text(
+                    "Add-ons",
+                    style = MaterialTheme.typography.titleMedium,
+                    modifier = Modifier.weight(1f),
+                )
+                TextButton(onClick = onDismiss) { Text("Done") }
+            }
+
+            if (loading) {
+                LinearProgressIndicator(Modifier.fillMaxWidth())
+            }
+
+            if (extensions.isEmpty() && !loading) {
+                Text(
+                    "No extensions installed",
+                    style = MaterialTheme.typography.bodyMedium,
+                    modifier = Modifier.padding(vertical = 24.dp),
+                )
+            }
+
+            LazyColumn(Modifier.weight(1f)) {
+                items(extensions, key = { it.id }) { ext ->
+                    val enabled = enabledStates[ext.id] ?: true
+                    Card(
+                        modifier = Modifier.fillMaxWidth().padding(vertical = 4.dp),
+                    ) {
+                        Row(
+                            Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
+                            verticalAlignment = Alignment.CenterVertically,
+                        ) {
+                            Column(Modifier.weight(1f)) {
+                                Text(
+                                    ext.name,
+                                    style = MaterialTheme.typography.bodyLarge,
+                                    maxLines = 1,
+                                    overflow = TextOverflow.Ellipsis,
+                                )
+                                Text(
+                                    if (ext.version.isBlank()) ext.id else "${ext.name.takeIf { false } ?: ext.id} · v${ext.version}",
+                                    style = MaterialTheme.typography.labelSmall,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                    maxLines = 1,
+                                    overflow = TextOverflow.Ellipsis,
+                                )
+                                if (ext.description.isNotBlank()) {
+                                    Text(
+                                        ext.description,
+                                        style = MaterialTheme.typography.bodySmall,
+                                        maxLines = 2,
+                                        overflow = TextOverflow.Ellipsis,
+                                    )
+                                }
+                            }
+                            Switch(
+                                checked = enabled,
+                                onCheckedChange = { checked -> onToggle(ext.id, checked) },
+                            )
+                        }
+                    }
+                }
+            }
+
+            Text(
+                "Bundled add-ons ship inside Nova; AMO (.xpi) installs arrive in M5.",
+                style = MaterialTheme.typography.labelSmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(top = 8.dp),
+            )
+        }
+    }
+}