fix(agent): 附件上传串行化修并发覆盖丢附件

app/src/main/java/com/aicode/feature/agent/presentation/component/AIChatPanel.kt

@@ -91,6 +91,8 @@ import java.io.File
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
 
 
 /**
@@ -491,6 +493,8 @@ fun AIChatPanel(
     }
     var pendingAttachments by remember { mutableStateOf<List<PendingUploadAttachment>>(emptyList()) }
     var uploadingCount by remember { mutableStateOf(0) }
+    // 串行化附件上传：两次上传并发时 pendingAttachments 的读-改-写会互相覆盖，导致先选的附件预览丢失。
+    val attachmentUploadMutex = remember { Mutex() }
     var messageForMenu by remember { mutableStateOf<AgentUIMessage?>(null) }
     var editingMessage by remember { mutableStateOf<AgentUIMessage?>(null) }
     val listState = rememberLazyListState()
@@ -709,20 +713,23 @@ fun AIChatPanel(
         scope.launch {
             var successCount = 0
             val failures = mutableListOf<String>()
-            uploadingCount = selected.size
-            try {
-                selected.forEach { uri ->
-                    runCatching {
-                        copyUriToWorkspace(context, uri, viewModel.fileAccess, includeImageData = images)
-                    }.onSuccess { uploaded ->
-                        pendingAttachments = pendingAttachments + uploaded.toPendingAttachment()
-                        successCount += 1
-                    }.onFailure { error ->
-                        failures += (error.message ?: uploadFallbackError(context))
+            // 串行化：并发上传会让 pendingAttachments 的读-改-写互相覆盖，先选的附件预览丢失。
+            attachmentUploadMutex.withLock {
+                uploadingCount = selected.size
+                try {
+                    selected.forEach { uri ->
+                        runCatching {
+                            copyUriToWorkspace(context, uri, viewModel.fileAccess, includeImageData = images)
+                        }.onSuccess { uploaded ->
+                            pendingAttachments = pendingAttachments + uploaded.toPendingAttachment()
+                            successCount += 1
+                        }.onFailure { error ->
+                            failures += (error.message ?: uploadFallbackError(context))
+                        }
                     }
+                } finally {
+                    uploadingCount = 0
                 }
-            } finally {
-                uploadingCount = 0
             }
             // 结果提示：全失败展示首个错误；有文件被上限截断或上传失败时用 partial 文案；全成功用 success 文案。
             val skipped = uris.size - selected.size

app/src/main/java/com/aicode/feature/agent/presentation/component/ChatInputAttachments.kt

@@ -32,6 +32,7 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
@@ -148,10 +149,15 @@ internal fun PendingAttachmentPreviewList(
 ) {
     if (attachments.isEmpty()) return
 
+    val scrollState = rememberScrollState()
+    // 新附件加入时自动滚到最右，保证刚上传的附件可见（横向滑动，不改竖向）。
+    LaunchedEffect(attachments.size) {
+        scrollState.animateScrollTo(scrollState.maxValue)
+    }
     Row(
         modifier = Modifier
             .fillMaxWidth()
-            .horizontalScroll(rememberScrollState())
+            .horizontalScroll(scrollState)
             .padding(horizontal = Spacing.xs, vertical = Spacing.xs),
         horizontalArrangement = Arrangement.spacedBy(Spacing.sm)
     ) {