feature: the package installs the Router Manager, which is no longer a package of its own.

docs/shell.md

@@ -0,0 +1,51 @@
+# Shell
+
+A login shell on the router, as your console account: your own POSIX account of the directory, or
+a local account root chose.
+
+- **Opening** asks for your password and code again, unless you used a shell within the router's
+  `web.shell_auth_timeout` minutes. **Open with a passkey** takes one of your passkeys instead,
+  unlocked with your device's PIN or biometrics; it shows when you have a passkey (see
+  [Account](account.md)).
+- **Closing:** the router ends the shell after `web.shell_idle_minutes` without a keystroke; the
+  page shows the reason and keeps the terminal readable.
+
+## Editor
+
+`vre FILE...` (or `vpn-router-editor FILE...`) in the shell opens the files in the editor of this
+page and returns at once:
+
+```sh
+vre /etc/hosts ~/notes.txt
+```
+
+- **Tabs:** each file has a tab with its name, and its path as the tooltip. A dot marks unsaved
+  changes, and the cross closes the tab, asking first when there are unsaved changes.
+- **Editor icon** (left of the shell icon): shown while a file is open. It switches between the
+  terminal and the editor; the shell keeps running.
+- **Minimap button** (left of Save): shows or hides the minimap at the right edge of the editor.
+  This browser remembers the choice.
+- **Save** (or Ctrl+S): writes the file on the router, as your console account. When the file
+  changed on the router after it was read, **Reload** takes the router's version and **Overwrite**
+  writes yours.
+- **Limits:** text files of up to 1 MiB, at most 20 at a time. A file that does not exist is
+  created when saved. A file your console account may not write cannot be saved; edit it in the
+  terminal.
+- **When files close:** when the shell ends, every file closes and the icon goes away. `vre`
+  works only in this shell.
+
+## Requirements
+
+- Membership of `admins`, enrolment for one-time passwords (see [Account](account.md)), also when
+  you open the shell with a passkey, as the router's login session and `sudo` need it, and console
+  login, which root switches on the router:
+
+  ```sh
+  vpn-router-user console <name> --posix
+  ```
+
+- The router offers the shell only while its `web.shell` is `true`:
+
+  ```sh
+  vpn-config-edit set web.shell true
+  ```