Give Enter and Space back to the control that has focus

Found while checking the keyboard could still reach the dealer button: it could
reach it and then couldn't press it.

Enter and Space were bound to "advance" for the whole document, with an exception
only for text fields. Those two keys are how a keyboard presses the control it is
sitting on, so every button on the page lost them -- and not to nothing. Measured:

  Tab to Resolve Pot, press Enter   ->  the table dealt the next hand
  Tab to Resolve Pot, press Space   ->  Resolve Pot, correctly
  Tab to a dealer button, Enter     ->  nothing at all

The inconsistency is the shortcut handler's return value. It calls preventDefault
only when it handled the key, so when "advance" applied it ran instead of the button,
and when it didn't apply the browser's own activation got through. A control that
does something else every other press is worse than one that does nothing.

Enter and Space now go to a focused button, [role=button], link or summary, and the
shortcut only claims them when nothing pressable has focus. The letters stay live
with a button focused -- a button does nothing with "f", and a dealer whose hand is
on the keys shouldn't lose them to a stray focus ring.

Space still advances the street: dealt, f, f, c, c, Space -> flop. The action bar
rebuilds itself after every press, so focus falls back to the body and the dealer's
Space is never quietly aimed at the Fold they just clicked.

11 tests (163 total), and they fail on the old handler -- 4 of them, exactly the
Enter/Space-on-a-control cases.

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

JoshHeaps.Net/wwwroot/js/casino/holdem/shortcuts.js

@@ -40,6 +40,22 @@ const Shortcuts = {
         return [...document.querySelectorAll('[id$="Overlay"]')].some(el => !el.hidden);
     },
 
+    // Enter and Space are how a keyboard presses the control it is already sitting on.
+    // Claiming them for "advance" didn't just block that press — it ran a different
+    // action instead. Measured: Tab to Resolve Pot, press Enter, and the table dealt
+    // the next hand. Space on the same button worked, because "advance" happened to
+    // decline that time and the browser's own activation got through. A control that
+    // does something else every other press is worse than one that does nothing.
+    //
+    // Only these two keys are handed back. The letter shortcuts stay live with a
+    // button focused, because a button does nothing with "f" and the dealer's hand
+    // shouldn't have to leave them.
+    focusedControlOwnsKey(key) {
+        if (key !== "enter" && key !== " ") return false;
+        const el = document.activeElement;
+        return !!(el && el.matches && el.matches('button, [role="button"], a[href], summary'));
+    },
+
     onKey(e) {
         if (e.metaKey || e.ctrlKey || e.altKey) return;
 
@@ -47,6 +63,8 @@ const Shortcuts = {
         const action = this.KEYS[key];
         if (!action) return;
 
+        if (this.focusedControlOwnsKey(key)) return;
+
         // Escape is the exception: it should still close the raise pad even if focus
         // happens to be sitting in its amount field.
         if (this.isTyping() && !(action === "cancel")) return;