Validate library doc file types before sending to Ivanti API

Library documents from the knowledge base were not checked against
the allowed file extensions before being sent to Ivanti. If a doc
had an unsupported type (e.g. .msg, .eml), Ivanti would reject the
entire workflow with a 400. Now validates library docs the same way
as local uploads and returns a clear error naming the offending file.

Allowed: .pdf, .png, .jpg, .jpeg, .gif, .doc, .docx, .xlsx, .csv, .txt, .zip

backend/routes/ivantiFpWorkflow.js

@@ -260,6 +260,12 @@ function createIvantiFpWorkflowRouter() {
                     const foundIds = new Set(libraryDocs.map(d => d.id));
                     const missingIds = libraryDocIds.filter(id => !foundIds.has(id));
                     if (missingIds.length > 0) return res.status(400).json({ error: `Library document IDs not found: ${missingIds.join(', ')}` });
+                    // Validate file types for library docs (same rules as local uploads)
+                    const unsupportedDocs = libraryDocs.filter(d => !isAllowedFileExtension(d.name));
+                    if (unsupportedDocs.length > 0) {
+                        const names = unsupportedDocs.map(d => d.name).join(', ');
+                        return res.status(400).json({ error: `Library document file type not supported by Ivanti: ${names}. Allowed: ${[...ALLOWED_EXTENSIONS].join(', ')}` });
+                    }
                 }
 
                 const libraryFormFiles = [];
@@ -821,6 +827,12 @@ function createIvantiFpWorkflowRouter() {
                     const foundIds = new Set(libraryDocs.map(d => d.id));
                     const missingIds = libraryDocIds.filter(id => !foundIds.has(id));
                     if (missingIds.length > 0) return res.status(400).json({ error: `Library document IDs not found: ${missingIds.join(', ')}` });
+                    // Validate file types for library docs
+                    const unsupportedDocs = libraryDocs.filter(d => !isAllowedFileExtension(d.name));
+                    if (unsupportedDocs.length > 0) {
+                        const names = unsupportedDocs.map(d => d.name).join(', ');
+                        return res.status(400).json({ error: `Library document file type not supported by Ivanti: ${names}. Allowed: ${[...ALLOWED_EXTENSIONS].join(', ')}` });
+                    }
                 }
 
                 const apiKey = process.env.IVANTI_API_KEY;