os/v3/puppy: a console-TUI message takes 9 Reboot / power off off the screen for 12 s in a 13-row window #1015

Found while sweeping the fourth "no half blocks" case (#1012 / #1014). Same family, different payer: the transient
message.

draw() builds the footer as [keys line] + [message] and wraps both into footer: Vec<Line>. The keys line and the
message are therefore charged the same way, and when actions + keys + message exceeds the frame, ratatui clips the END
of the MENU — the ninth action — for as long as the message lives (12 s, main.rs's Duration::from_secs(12)).

Measured (blank-key mode, c16_board(), TERM=linux):

So the trigger is a window where actions + keys <= h < actions + keys + message — 40x13 is the clean case: the same
window draws all nine until a key is pressed, then loses Reboot / power off (a vm-check.sh / menugate string) for
twelve seconds. Full-log view (key 8) is unaffected.

No gate impact: the gates run at 80x25 and 240x67, where the frame has room for all of it.

The fix is a priority decision, which is why it is an issue and not a commit tonight — three options, in increasing size:

1. Drop the message when it would cost an action row (actions + keys + message > h). Smallest diff, but the
   messages include real feedback ("reboot returned - the box did not go down", a handoff exit status), and silence is
   indistinguishable from a dead key.
2. Wrap the message to at most one row in that case (cost 1 row instead of 2). Keeps feedback; the message is cut
   mid-word, which the file's "nothing is drawn half a block" rule otherwise forbids.
3. Trim the keys line's legend tail before the message — the gate string is 1-9 actions (checked:
   puppy-check.sh and menugate.sh key the TUI shape on 1-9 actions or 1 Show the API key; nothing greps
   arrows/refresh/q stays), so 1-9 actions arrows scroll f newest r fits on one row at 40 columns and frees the
   row the message needs. Keeps the gate string, keeps the message, costs legend text that only the footer carries.

I would take 3, then 1 for anything narrower. Owner's call if the legend matters more than the message.

Not fixed here so that #1014 stays one idea; recorded because the sweep found it and it is the last size-related way the
MENU can lose a row.