feat(core): the file explorer, text editor and image viewer's file operations after Java, measured against Java

FileCases does what the windows of FILIUS' file explorer and text editor
do to a host's files: new folder, delete, copy, cut and paste, rename,
import, save and save as. The core's filePrograms.ts does the same on the
node's file system; the file system renames an entry in its place, as
Java's tree does.

Departures from Java: a folder name that comes to no name makes nothing,
a paste onto a name there already is refused, a rename to a name with a
slash or blanks at its ends is refused and one of the case only is done,
save as and import onto a folder's name are refused.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/core/src/index.ts

@@ -26,6 +26,7 @@ export * from './runtime/apps/routerPages.js';
 export * from './runtime/apps/firewallSettings.js';
 export * from './runtime/apps/emailServer.js';
 export * from './runtime/apps/emailClient.js';
+export * from './runtime/apps/filePrograms.js';
 export * from './runtime/apps/terminal.js';
 export * from './runtime/apps/terminalTexts.js';
 export * from './runtime/email.js';