Fix: table parser metadata (#15127)

### What problem does this PR solve?

This PR improves the table upload flow for CSV/Excel files by allowing
table column role configuration at upload time.

Previously, users had to:
1. Upload and parse a table file.
2. Open parser settings and manually set table column roles.
3. Re-parse the file for the roles to take effect.

This was inefficient and required an unnecessary second parse.

With this change:
1. When the knowledge base uses table parsing, the upload dialog
extracts CSV/Excel headers client-side.
2. Users can choose Auto mode or Manual mode.
3. In Manual mode, users can assign per-column roles before upload.
4. The selected parser config is sent with the upload request and
applied server-side during document creation.

Result: configured table column roles are applied from the first parse.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

Co-authored-by: Ahmad Intisar <ahmadintisar@Ahmads-MacBook-M4-Pro.local>

web/src/pages/dataset/dataset/index.tsx

@@ -242,6 +242,7 @@ export default function Dataset() {
             onOk={onDocumentUploadOk}
             loading={documentUploadLoading}
             showParseOnCreation
+            isTableParser={knowledgeBase?.chunk_method === 'table'}
           ></FileUploadDialog>
         )}
         {createVisible && (

web/src/pages/dataset/dataset/use-upload-document.ts

@@ -17,9 +17,27 @@ export const useHandleUploadDocument = () => {
   const { runDocumentByIds } = useRunDocument();
 
   const onDocumentUploadOk = useCallback(
-    async ({ fileList, parseOnCreation }: UploadFormSchemaType) => {
+    async ({
+      fileList,
+      parseOnCreation,
+      tableColumnMode,
+      tableColumnRoles,
+    }: UploadFormSchemaType) => {
       if (fileList.length > 0) {
-        const ret = await uploadDocument(fileList);
+        // Build parser_config if column roles are configured
+        let parserConfig: Record<string, any> | undefined;
+        if (
+          tableColumnMode === 'manual' &&
+          tableColumnRoles &&
+          Object.keys(tableColumnRoles).length > 0
+        ) {
+          parserConfig = {
+            table_column_mode: 'manual',
+            table_column_roles: tableColumnRoles,
+          };
+        }
+
+        const ret = await uploadDocument(fileList as File[], parserConfig);
 
         // Check for success (code === 0) or partial success (code === 500 with some files)
         const isSuccess = ret?.code === 0;