Keep every bot's computer work in its own workspace folder

Computers now mount only /home/gem/workspace from DATA_DIR/computers/<id>,
so only the workspace persists and goes into the data archive. An older
computer's whole home is moved aside to <id>-home-<ts> (kept, never
archived) and its container recreated once by sync-computers.

Each run works in bots/<bot>/users/<user> (also its cwd and HOME), with
bots/<bot> for work every user shares and workspaces/<id> shared by a
workspace's bots; the coordinator reaches the whole workspace. Computer
tools are gated by withComputerDirs: bash and code start there, file tool
paths and file: URLs outside the run's folders are refused, and so is sudo.
search_computers, import_file and script tools start there too.

The files browser shows members only the bots' folders they reach, their
own user folder in each and their workspaces', with names on the id folders.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/dict/computer-dict.ts

@@ -1,7 +1,8 @@
 /**
  * A computer is an AIO sandbox running in its own docker container on the
- * cobble network, created by the app (`createComputer`), its home
- * directory kept under `DATA_DIR/computers/<id>`.
+ * cobble network, created by the app (`createComputer`), only its
+ * workspace (`AppData.ComputerWorkspaceDir`) kept under
+ * `DATA_DIR/computers/<id>`.
  */
 export const ComputerKinds = [
     {