fix: msteams attachments + plugin prompt hints

Co-authored-by: Christof <10854026+Evizero@users.noreply.github.com>

extensions/msteams/src/file-consent-helpers.ts

@@ -0,0 +1,73 @@
+/**
+ * Shared helpers for FileConsentCard flow in MSTeams.
+ *
+ * FileConsentCard is required for:
+ * - Personal (1:1) chats with large files (>=4MB)
+ * - Personal chats with non-image files (PDFs, documents, etc.)
+ *
+ * This module consolidates the logic used by both send.ts (proactive sends)
+ * and messenger.ts (reply path) to avoid duplication.
+ */
+
+import { buildFileConsentCard } from "./file-consent.js";
+import { storePendingUpload } from "./pending-uploads.js";
+
+export type FileConsentMedia = {
+  buffer: Buffer;
+  filename: string;
+  contentType?: string;
+};
+
+export type FileConsentActivityResult = {
+  activity: Record<string, unknown>;
+  uploadId: string;
+};
+
+/**
+ * Prepare a FileConsentCard activity for large files or non-images in personal chats.
+ * Returns the activity object and uploadId - caller is responsible for sending.
+ */
+export function prepareFileConsentActivity(params: {
+  media: FileConsentMedia;
+  conversationId: string;
+  description?: string;
+}): FileConsentActivityResult {
+  const { media, conversationId, description } = params;
+
+  const uploadId = storePendingUpload({
+    buffer: media.buffer,
+    filename: media.filename,
+    contentType: media.contentType,
+    conversationId,
+  });
+
+  const consentCard = buildFileConsentCard({
+    filename: media.filename,
+    description: description || `File: ${media.filename}`,
+    sizeInBytes: media.buffer.length,
+    context: { uploadId },
+  });
+
+  const activity: Record<string, unknown> = {
+    type: "message",
+    attachments: [consentCard],
+  };
+
+  return { activity, uploadId };
+}
+
+/**
+ * Check if a file requires FileConsentCard flow.
+ * True for: personal chat AND (large file OR non-image)
+ */
+export function requiresFileConsent(params: {
+  conversationType: string | undefined;
+  contentType: string | undefined;
+  bufferSize: number;
+  thresholdBytes: number;
+}): boolean {
+  const isPersonal = params.conversationType?.toLowerCase() === "personal";
+  const isImage = params.contentType?.startsWith("image/") ?? false;
+  const isLargeFile = params.bufferSize >= params.thresholdBytes;
+  return isPersonal && (isLargeFile || !isImage);
+}