fix(kb): guard stuck document retry against filenames without extension

Existing DB rows may have connector document filenames stored without
a .txt extension (raw meeting titles). The stuck-doc retry path reads
filename from DB and passes it to parseHttpFile, which extracts the
extension via split('.'). When there's no dot, the entire title
becomes the "extension", causing "Unsupported file type" errors.

Falls back to 'document.txt' when the stored filename has no extension.

Author: waleedlatif1

apps/sim/lib/knowledge/connectors/sync-engine.ts

@@ -562,7 +562,8 @@ export async function executeSync(
           connector.knowledgeBaseId,
           doc.id,
           {
-            filename: doc.filename ?? 'document.txt',
+            filename:
+              doc.filename && doc.filename.includes('.') ? doc.filename : 'document.txt',
             fileUrl: doc.fileUrl ?? '',
             fileSize: doc.fileSize ?? 0,
             mimeType: 'text/plain',