feat: support multiple file upload in Attachments component (#13283)

Closes #13277

## What I Did

- Enabled `multiple` attribute in the file input
- Updated the `handleFileChange` handler to loop through files
- Confirmed that each file is sent via `uploadAttachmentFile`

## Why

This change allows users to upload multiple files at once instead of
doing it one by one.

## Screenshot / Video (Optional)
[Screencast From 2025-07-18
23-58-36.webm](https://github.com/user-attachments/assets/ea191f25-1904-4643-afe2-7029785eebcb)


---
Let me know if you'd like any changes! 💪

---------

Co-authored-by: Félix Malfait <felix@twenty.com>

packages/twenty-front/src/modules/activities/files/components/AttachmentList.tsx

@@ -137,6 +137,12 @@ export const AttachmentList = ({
     await uploadAttachmentFile(file, targetableObject);
   };
 
+  const onUploadFiles = async (files: File[]) => {
+    for (const file of files) {
+      await onUploadFile(file);
+    }
+  };
+
   const handlePreview = (attachment: Attachment) => {
     if (!isAttachmentPreviewEnabled) return;
     setPreviewedAttachment(attachment);
@@ -167,7 +173,7 @@ export const AttachmentList = ({
             {isDraggingFile ? (
               <DropZone
                 setIsDraggingFile={setIsDraggingFile}
-                onUploadFile={onUploadFile}
+                onUploadFiles={onUploadFiles}
               />
             ) : (
               <ActivityList>

packages/twenty-front/src/modules/activities/files/components/Attachments.tsx

@@ -48,18 +48,26 @@ export const Attachments = ({
 
   const [isDraggingFile, setIsDraggingFile] = useState(false);
 
+  const onUploadFile = async (file: File) => {
+    await uploadAttachmentFile(file, targetableObject);
+  };
+
+  const onUploadFiles = async (files: File[]) => {
+    for (const file of files) {
+      await onUploadFile(file);
+    }
+  };
+
   const handleFileChange = (e: ChangeEvent<HTMLInputElement>) => {
-    if (isDefined(e.target.files)) onUploadFile?.(e.target.files[0]);
+    if (isDefined(e.target.files)) {
+      onUploadFiles(Array.from(e.target.files));
+    }
   };
 
   const handleUploadFileClick = () => {
     inputFileRef?.current?.click?.();
   };
 
-  const onUploadFile = async (file: File) => {
-    await uploadAttachmentFile(file, targetableObject);
-  };
-
   const isAttachmentsEmpty = !attachments || attachments.length === 0;
 
   const { objectMetadataItem } = useObjectMetadataItem({
@@ -82,7 +90,7 @@ export const Attachments = ({
         {isDraggingFile ? (
           <DropZone
             setIsDraggingFile={setIsDraggingFile}
-            onUploadFile={onUploadFile}
+            onUploadFiles={onUploadFiles}
           />
         ) : (
           <AnimatedPlaceholderEmptyContainer
@@ -102,6 +110,7 @@ export const Attachments = ({
               ref={inputFileRef}
               onChange={handleFileChange}
               type="file"
+              multiple
             />
             {hasObjectUpdatePermissions && (
               <Button
@@ -123,6 +132,7 @@ export const Attachments = ({
         ref={inputFileRef}
         onChange={handleFileChange}
         type="file"
+        multiple
       />
       <AttachmentList
         targetableObject={targetableObject}

packages/twenty-front/src/modules/activities/files/components/DropZone.tsx

@@ -1,6 +1,6 @@
-import { useDropzone } from 'react-dropzone';
 import { useTheme } from '@emotion/react';
 import styled from '@emotion/styled';
+import { useDropzone } from 'react-dropzone';
 
 import { useSpreadsheetImportInternal } from '@/spreadsheet-import/hooks/useSpreadsheetImportInternal';
 import { IconUpload } from 'twenty-ui/display';
@@ -40,12 +40,12 @@ const StyledUploadIcon = styled(IconUpload)`
 
 type DropZoneProps = {
   setIsDraggingFile: (drag: boolean) => void;
-  onUploadFile: (file: File) => void;
+  onUploadFiles: (files: File[]) => void;
 };
 
 export const DropZone = ({
   setIsDraggingFile,
-  onUploadFile,
+  onUploadFiles,
 }: DropZoneProps) => {
   const theme = useTheme();
   const { maxFileSize } = useSpreadsheetImportInternal();
@@ -53,7 +53,7 @@ export const DropZone = ({
   const { getRootProps, getInputProps, isDragActive } = useDropzone({
     noClick: true,
     noKeyboard: true,
-    maxFiles: 1,
+    multiple: true,
     maxSize: maxFileSize,
     onDragEnter: () => {
       setIsDraggingFile(true);
@@ -64,8 +64,8 @@ export const DropZone = ({
     onDrop: () => {
       setIsDraggingFile(false);
     },
-    onDropAccepted: async ([file]) => {
+    onDropAccepted: async (files) => {
-      onUploadFile(file);
+      onUploadFiles(files);
       setIsDraggingFile(false);
     },
   });
@@ -85,7 +85,7 @@ export const DropZone = ({
             stroke={theme.icon.stroke.sm}
             size={theme.icon.size.lg}
           />
-          <StyledUploadDragTitle>Upload a file</StyledUploadDragTitle>
+          <StyledUploadDragTitle>Upload files</StyledUploadDragTitle>
           <StyledUploadDragSubTitle>
             Drag and Drop Here
           </StyledUploadDragSubTitle>

packages/twenty-front/src/modules/workflow/workflow-steps/workflow-actions/ai-agent-action/components/AIChatTab.tsx

@@ -85,7 +85,7 @@ export const AIChatTab = ({
       {isDraggingFile && (
         <DropZone
           setIsDraggingFile={setIsDraggingFile}
-          onUploadFile={(files) => uploadFiles([files])}
+          onUploadFiles={uploadFiles}
         />
       )}
       {!isDraggingFile && (