Let the terminal's text be made bigger, and remember how big

Taking pinch-zoom off the phone left nothing in its place, and there was nothing on the desktop
either. This is the replacement, and it is deliberately not the thing that was removed: zoom scales
what has already been drawn, so the remote goes on wrapping to a width that is no longer on screen.
Changing the font size refits the grid and reports the new column count, so the far end is told it
has fewer columns. That round trip is the feature.

The size is one number, owned by the shell. It has to be, for two reasons that pull the same way: it
must survive a relaunch, and it must be reachable from a phone that has no Ctrl key to press. So the
page asks and the host decides — a signed step over a new client opcode, answered with a size over a
new server opcode. The phone's buttons and the desktop's chords arrive at the same place, and a size
set by either is the size both remember.

Stored in settings.json beside the cache rather than in it, and that is not laziness about a
migration. The cache is encrypted and unreadable until a vault is unlocked, and the first terminal of
a locked launch needs the size already. Nothing secret may go in that file; ClientSettings says so
out loud, because the next person to add a preference is the one who needs to read it.

Where it is reachable from differs per head, and only here. The phone gets A− and A+ on the
connection line — not in the accessory row, which scrolls, and a control that fixes unreadable text
must never be the thing that is off-screen. The desktop gets the three chords every terminal
emulator has, answered by the page while a terminal has focus and by the window when it does not,
plus a row in preferences that shows the current value and names the chords rather than replacing
them. Someone whose terminal is too small to read is not in a position to go looking.

Clamped 8 to 32. Below eight a monospace grid stops being legible and becomes a texture, and every
column of it is still a column the remote is being told exists; above thirty-two a phone in portrait
has too few columns to hold a prompt. The buttons disable at the ends rather than accepting presses
that do nothing, which on a terminal reads as the application having stopped responding.

The preferences screen's header comment claimed none of the design's terminal settings could be
saved, and listed the three things that were missing to make one work. All three now exist, so it
says which one is real and why the other five still are not.

Verified with the protocol suite — including that the step byte round-trips signed, since read
unsigned a step down arrives as 255 and clamps to the largest font, making "smaller" do the most
dramatic available version of "larger" — a data-plane test that the chord is heard with no session
registered, and five shell tests: the default matches the renderer's, both clamps hold, reset works,
and a size chosen in one shell is there in a second one over the same profile directory. Layout
suite and both heads build.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/DodoSSH.Client.App/Views/PreferencesScreen.axaml

@@ -8,11 +8,13 @@
   <!--
     Preferences.
 
-    The design's rail has six sections and its TERMINAL panel has six settings. None of the six settings can
-    be saved: there is no preferences table in the local cache, no preference item type in the vault, and no
-    channel from the host to the renderer that carries a terminal option — the data plane's frames are
-    output, session-opened, session-closed and session-activated, and nothing else. A font-size stepper
-    that reset on every launch would be worse than not having one.
+    The design's rail has six sections and its TERMINAL panel has six settings. One of those six is now
+    real: text size. It needed all three of the things this comment used to record as missing — somewhere
+    to keep a preference (settings.json beside the cache, outside it deliberately, so it can be read on a
+    launch that never unlocks anything), a frame carrying a terminal option (TerminalServerOpcode.FontSize),
+    and a way for the page's own chords to reach the host that owns the value
+    (TerminalClientOpcode.FontSizeStep). The rule that kept it off this screen until then still stands and
+    is why the storage came first: a stepper that reset on every launch is worse than no stepper.
 
     So this screen ships what is real, which is not nothing: this machine's device key is a genuine
     preference with a genuine effect, and it is the one thing on the design's SECURITY panel that exists.
@@ -59,6 +61,40 @@
 
       <Border Height="1" Background="{StaticResource BorderSubtle}" Margin="0,20" />
 
+      <TextBlock Classes="mono" Text="TERMINAL" FontSize="13" FontWeight="SemiBold"
+                 LetterSpacing="1" Foreground="{StaticResource Text}" />
+
+      <!--
+        Here as well as on the chord, and not because the chord is in doubt. Ctrl+plus can only be heard
+        while a terminal has focus, since that is where the keyboard is being read — so somebody who has
+        not opened one yet, or who has just made the text too small to find anything in, has nowhere else
+        to look. This is that place, and it names the chord so the screen teaches it rather than replacing
+        it.
+      -->
+      <Grid ColumnDefinitions="*,Auto" Margin="0,12,0,0">
+        <StackPanel Grid.Column="0" Spacing="2" Margin="0,0,16,0">
+          <TextBlock Text="Text size" Foreground="{StaticResource Text}" FontSize="12"
+                     FontWeight="Medium" />
+          <TextBlock Classes="hint" FontSize="10"
+                     Text="How large a terminal draws, in pixels. Ctrl+plus and Ctrl+minus do the same while a terminal has focus, and Ctrl+0 puts it back. It resizes the grid rather than magnifying it, so the remote is told how many columns it now has — which is also why it stops before the columns run out." />
+        </StackPanel>
+        <StackPanel Grid.Column="1" Orientation="Horizontal" Spacing="6" VerticalAlignment="Top">
+          <Button Classes="ghost" Content="A−" Command="{Binding ShrinkTerminalFontCommand}"
+                  IsEnabled="{Binding CanShrinkTerminalFont}"
+                  ToolTip.Tip="Smaller  ·  Ctrl+minus" />
+          <TextBlock Classes="mono" FontSize="12" MinWidth="26" VerticalAlignment="Center"
+                     TextAlignment="Center" Foreground="{StaticResource Text}"
+                     Text="{Binding TerminalFontSize}" />
+          <Button Classes="ghost" Content="A+" Command="{Binding EnlargeTerminalFontCommand}"
+                  IsEnabled="{Binding CanEnlargeTerminalFont}"
+                  ToolTip.Tip="Larger  ·  Ctrl+plus" />
+          <Button Classes="ghost" Content="RESET" Command="{Binding ResetTerminalFontCommand}"
+                  ToolTip.Tip="Back to the size it ships at  ·  Ctrl+0" />
+        </StackPanel>
+      </Grid>
+
+      <Border Height="1" Background="{StaticResource BorderSubtle}" Margin="0,20" />
+
       <TextBlock Classes="mono" Text="KEYCHAIN" FontSize="13" FontWeight="SemiBold"
                  LetterSpacing="1" Foreground="{StaticResource Text}" />