fix: msteams attachments + plugin prompt hints

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

src/media/store.ts

@@ -11,6 +11,43 @@ const resolveMediaDir = () => path.join(resolveConfigDir(), "media");
 const MAX_BYTES = 5 * 1024 * 1024; // 5MB default
 const DEFAULT_TTL_MS = 2 * 60 * 1000; // 2 minutes
 
+/**
+ * Sanitize a filename for cross-platform safety.
+ * Removes chars unsafe on Windows/SharePoint/all platforms.
+ * Keeps: alphanumeric, dots, hyphens, underscores, Unicode letters/numbers.
+ */
+function sanitizeFilename(name: string): string {
+  // Remove: < > : " / \ | ? * and control chars (U+0000-U+001F)
+  // oxlint-disable-next-line no-control-regex -- Intentionally matching control chars
+  const unsafe = /[<>:"/\\|?*\x00-\x1f]/g;
+  const sanitized = name.trim().replace(unsafe, "_").replace(/\s+/g, "_"); // Replace whitespace runs with underscore
+  // Collapse multiple underscores, trim leading/trailing, limit length
+  return sanitized.replace(/_+/g, "_").replace(/^_|_$/g, "").slice(0, 60);
+}
+
+/**
+ * Extract original filename from path if it matches the embedded format.
+ * Pattern: {original}---{uuid}.{ext} → returns "{original}.{ext}"
+ * Falls back to basename if no pattern match, or "file.bin" if empty.
+ */
+export function extractOriginalFilename(filePath: string): string {
+  const basename = path.basename(filePath);
+  if (!basename) return "file.bin"; // Fallback for empty input
+
+  const ext = path.extname(basename);
+  const nameWithoutExt = path.basename(basename, ext);
+
+  // Check for ---{uuid} pattern (36 chars: 8-4-4-4-12 with hyphens)
+  const match = nameWithoutExt.match(
+    /^(.+)---[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}$/i,
+  );
+  if (match?.[1]) {
+    return `${match[1]}${ext}`;
+  }
+
+  return basename; // Fallback: use as-is
+}
+
 export function getMediaDir() {
   return resolveMediaDir();
 }
@@ -152,17 +189,29 @@ export async function saveMediaBuffer(
   contentType?: string,
   subdir = "inbound",
   maxBytes = MAX_BYTES,
+  originalFilename?: string,
 ): Promise<SavedMedia> {
   if (buffer.byteLength > maxBytes) {
     throw new Error(`Media exceeds ${(maxBytes / (1024 * 1024)).toFixed(0)}MB limit`);
   }
   const dir = path.join(resolveMediaDir(), subdir);
   await fs.mkdir(dir, { recursive: true });
-  const baseId = crypto.randomUUID();
+  const uuid = crypto.randomUUID();
   const headerExt = extensionForMime(contentType?.split(";")[0]?.trim() ?? undefined);
   const mime = await detectMime({ buffer, headerMime: contentType });
-  const ext = headerExt ?? extensionForMime(mime);
-  const id = ext ? `${baseId}${ext}` : baseId;
+  const ext = headerExt ?? extensionForMime(mime) ?? "";
+
+  let id: string;
+  if (originalFilename) {
+    // Embed original name: {sanitized}---{uuid}.ext
+    const base = path.parse(originalFilename).name;
+    const sanitized = sanitizeFilename(base);
+    id = sanitized ? `${sanitized}---${uuid}${ext}` : `${uuid}${ext}`;
+  } else {
+    // Legacy: just UUID
+    id = ext ? `${uuid}${ext}` : uuid;
+  }
+
   const dest = path.join(dir, id);
   await fs.writeFile(dest, buffer);
   return { id, path: dest, size: buffer.byteLength, contentType: mime };