Add keyboard control for a dealer working on a laptop

The phone got gestures a few rounds back; the desktop still had a mouse and
nothing else. On a bar that gets tapped thirty times a hand, moving a hand to
the trackpad between every decision is the slow part.

F folds, C checks or calls, R opens the raise pad, A shoves, Enter confirms a
raise or moves the hand on, Esc backs out, U takes the last action back. Each
button wears its key in the corner, hidden on touch devices where it would just
be clutter on a button being tapped anyway.

The shortcuts press the same buttons a dealer would tap rather than calling the
betting engine themselves, so there's no second code path to drift out of step
with what the bar is actually offering — if a button isn't on screen, its key
does nothing.

Nothing fires while a name, amount or note is being typed, or while an overlay
owns the keyboard. Typing "Francesca" into a seat name must not fold the table.

Co-Authored-By: Claude Sonnet 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_015bnp7xKUPFFSpwkYNFaPgb

JoshHeaps.Net/Pages/Casino/TexasHoldem.cshtml

@@ -294,6 +294,7 @@
     <script src="~/js/casino/holdem/seatMenu.js?v=@ViewData["cssVersion"]"></script>
     <script src="~/js/casino/holdem/betting.js?v=@ViewData["cssVersion"]"></script>
     <script src="~/js/casino/holdem/actionBar.js?v=@ViewData["cssVersion"]"></script>
+    <script src="~/js/casino/holdem/shortcuts.js?v=@ViewData["cssVersion"]"></script>
     <script src="~/js/casino/holdem/potWizard.js?v=@ViewData["cssVersion"]"></script>
     <script src="~/js/casino/holdem/handHistoryExport.js?v=@ViewData["cssVersion"]"></script>
     <script src="~/js/casino/holdem/main.js?v=@ViewData["cssVersion"]"></script>