feat(chat): the input row learns the window's own language

Five filled plates become two ghost buttons and a menu. The plates were ImGui
defaults sitting between a drawn pill and a drawn status bar -- three shape
languages in the one row a user works in, which is what the tester's screenshot
made obvious. The ghosts follow the sidebar's icon buttons: nothing at rest, a
held hover fill, the glyph lifting toward the accent.

Symbols stay outside the menu because they are used mid-sentence. Theme,
settings, screenshot and hide move in; the screenshot toggle was allowed in only
because its state moved to the status bar first, as an accent pill that shows
while the mode is on. A privacy state behind a closed menu answers nothing.

The input field paints its own rounded surface and hands ImGui a transparent
frame, so the widget draws only text and caret -- the Boutique.Inputs technique
from Character Select+, no rebuild of the widget itself. Focus is a two-pixel
accent rail on the left edge: the same mark the rows, the popups and the message
list already use for "this is where you are".

The channel pill gets the CS+ treatment, a faint white gradient and a one-pixel
light along the top edge. White over the fill rather than a second hue, so it
reads as depth in every palette.

And the popups that open from the row are made of PopupRow now -- the sidebar
row's shape, which is also exactly what CS+ draws for its own popup entries. The
channel picker was the reported case: a drawn pill opening a list of naked
selectables, the style breaking mid-click.

A hundred-odd pixels of button reserve go back to the input field.

HellionChat/Resources/HellionStrings.ko.resx

@@ -1361,4 +1361,7 @@
   <data name="ChannelHeader_NotLoggedIn" xml:space="preserve">
     <value>로그인되지 않음</value>
   </data>
+  <data name="InputBar_More_Tooltip" xml:space="preserve">
+    <value>추가 작업</value>
+  </data>
 </root>