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/runtime/apps/terminal.ts

@@ -94,7 +94,7 @@ const USAGE: Record<string, string> = {
  * Dateisystem.evaluatePathString for an absolute path: "." and empty parts
  * left out, ".." one up (at the root it stays there).
  */
-function evaluatedPath(path: string): string {
+export function evaluatedPath(path: string): string {
   const parts: string[] = [];
   for (const part of path.split('/')) {
     if (part === '..') parts.pop();