folder upload file extensions

frontend/components/knowledge-dropdown.tsx

@@ -251,10 +251,26 @@ export function KnowledgeDropdown() {
         ".pdf",
         ".doc",
         ".docx",
+        ".pptx",
+        ".ppt",
+        ".xlsx",
+        ".xls",
+        ".csv",
         ".txt",
         ".md",
+        ".html",
+        ".htm",
         ".rtf",
         ".odt",
+        ".asciidoc",
+        ".adoc",
+        ".png",
+        ".jpg",
+        ".jpeg",
+        ".gif",
+        ".bmp",
+        ".tiff",
+        ".webp",
       ];
 
       const filteredFiles = fileList.filter((file) => {