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/wwwroot/css/casino/holdem.css

@@ -1219,6 +1219,7 @@ body.hasActionBar #holdemSidebar {
 }
 
 .actionBtn {
+    position: relative;
     flex: 1;
     display: flex;
     flex-direction: column;
@@ -1256,6 +1257,29 @@ body.hasActionBar #holdemSidebar {
     font-variant-numeric: tabular-nums;
 }
 
+.actionKey {
+    position: absolute;
+    top: 5px;
+    right: 7px;
+    padding: 0 0.25rem;
+    border-radius: 4px;
+    border: 1px solid currentColor;
+    opacity: 0.4;
+    font-family: inherit;
+    font-size: 0.6rem;
+    line-height: 1.4;
+    text-transform: uppercase;
+    pointer-events: none;
+}
+
+/* No keyboard, no key badges — on a phone they'd just be clutter on the buttons
+   the dealer is already tapping. */
+@media (hover: none) {
+    .actionKey {
+        display: none;
+    }
+}
+
 .actionFold {
     background: linear-gradient(180deg, #3d1f1f, #2c1515);
     border-color: #5b2626;