feat: add max file count validation for OneDrive file selection

src/lib/components/chat/MessageInput.svelte

@@ -1547,7 +1547,11 @@
 										}}
 										uploadOneDriveHandler={async (authorityType) => {
 											try {
-												const filesData = await pickAndDownloadFiles(authorityType);
+												const maxFileCount = $config?.file?.max_count;
+												const filesData = await pickAndDownloadFiles(
+													authorityType,
+													maxFileCount
+												);
 												if (filesData && filesData.length > 0) {
 													if (filesData.length > 1) {
 														toast.success(
@@ -1568,11 +1572,22 @@
 												}
 											} catch (error) {
 												console.error('OneDrive Error:', error);
-												toast.error(
-													$i18n.t('OneDrive Error: {{error}}', {
-														error: error.message
-													})
-												);
+												// Handle specific max file count error
+												if (error.message?.startsWith('MAX_FILE_COUNT_EXCEEDED:')) {
+													const [, count, max] = error.message.split(':');
+													toast.error(
+														$i18n.t('Selected items contain {{count}} files, but maximum is {{max}}.', {
+															count,
+															max
+														})
+													);
+												} else {
+													toast.error(
+														$i18n.t('OneDrive Error: {{error}}', {
+															error: error.message
+														})
+													);
+												}
 											}
 										}}
 										{onUpload}

src/lib/utils/onedrive-file-picker.ts

@@ -501,7 +501,8 @@ export async function openOneDrivePicker(
 
 // Pick and download multiple files from OneDrive (with folder support)
 export async function pickAndDownloadFiles(
-	authorityType?: 'personal' | 'organizations'
+	authorityType?: 'personal' | 'organizations',
+	maxFileCount?: number
 ): Promise<{ blob: Blob; name: string }[] | null> {
 	const pickerResult = await openOneDrivePicker(authorityType);
 
@@ -528,6 +529,13 @@ export async function pickAndDownloadFiles(
 		throw new Error('No files found in the selected items.');
 	}
 
+	// Check if the number of files exceeds the configured maximum
+	if (maxFileCount && allFiles.length > maxFileCount) {
+		throw new Error(
+			`MAX_FILE_COUNT_EXCEEDED:${allFiles.length}:${maxFileCount}`
+		);
+	}
+
 	// Download all files with error handling
 	const downloadPromises = allFiles.map(async (fileInfo) => {
 		const blob = await downloadOneDriveFile(fileInfo, authorityType);