Screenshots: Fn+p on every screen (#83)

Fn+p saves the screen as it is to /screenshots, as the Shell's `screenshot`
does, from anywhere: text fields, dialogs and the help panel included. The
key never reaches an App.

It refuses on Settings > Debug Console, which shows the token: a picture of
that page is a copy of the token in a file (App::showsSecret). `key shot`
presses it over the consoles.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

site/content/dev/debug/commands.md

@@ -29,7 +29,7 @@ gnss quiet on|off   pause the GNSS receiver while the LoRa radio listens (it cos
 gnss status | gnss restart | gnss track start|stop | gnss nmea on|off | gnss send <sentence without $ and checksum>
 crash             the last crash: firmware, reason, task, backtrace
 coredump erase    forget the core dump in flash
-key <name|char>   press a key: up down left right select back home del tab space help, or one character; ctrl- alt- shift- before it (key ctrl-down)
+key <name|char>   press a key: up down left right select back home del tab space help shot, or one character; ctrl- alt- shift- before it (key ctrl-down)
 wifi status | wifi add <ssid><TAB><password>
 wifi ip <ssid> dhcp | wifi ip <ssid> <address>/<prefix> [gateway]   a Saved Network's IP setting
 wifi dns <a> [b] | wifi dns always on|off | wifi ntp <a> [b]   DNS and NTP servers
@@ -62,7 +62,7 @@ In **Safe Mode** (see [Crashes and Safe Mode](/dev/debug/crashes/)) only a few r
 | Command | Effect |
 |---|---|
 | `burst` | Publishes 5 Notifications at once |
-| `key up\|down\|left\|right\|select\|back\|home\|del\|tab\|space\|help`, or `key <char>` | Injects a key press (`help` is Fn+h: the keys of the screen that is showing). `ctrl-`, `alt-` and `shift-` before it hold that key: `key ctrl-down`, `key alt-up`, `key ctrl-b` |
+| `key up\|down\|left\|right\|select\|back\|home\|del\|tab\|space\|help\|shot`, or `key <char>` | Injects a key press (`help` is Fn+h: the keys of the screen that is showing; `shot` is Fn+p: a screenshot). `ctrl-`, `alt-` and `shift-` before it hold that key: `key ctrl-down`, `key alt-up`, `key ctrl-b` |
 | `sound on` / `sound off` | Toggles the Sound setting (beep + LED) |
 | `short` / `normal` | Screen timeouts 5 s / 10 s, or 30 s / 60 s |
 | `wifi add <ssid><TAB><password>` | Adds a Saved Network (so credentials stay out of the repo) |