Explain portable storage path policy

src/apps/storagePath.ts

@@ -10,6 +10,8 @@ export function validateStoragePath(storagePath: string, allowRoot: boolean = tr
         throw new Error("The storage root is not a valid entry path");
     }
 
+    // LiveSync normally rejects ':' in portable filenames before paths reach storage. A leading letter and colon
+    // therefore represents drive-qualified input or a leaked non-storage namespace, not a supported physical path.
     if (storagePath.startsWith("/") || storagePath.startsWith("\\") || /^[A-Za-z]:/.test(storagePath)) {
         throw new Error(`Storage paths must be relative to the configured root: ${storagePath}`);
     }