Stop calling it the next hand when it deals no hand

"Next hand" named three things: the bar's green button, the pot wizard's
last button, and the header shortcut — the only one of the three that
never starts a hand. Between hands it moves the button a second time, so
the seat about to pay the big blind is skipped, and the toast opened with
the words the wizard had just used, which read as a confirmation of what
was already done.

Measured: settle through the wizard and the table is on hand 6 with the
button on seat 2; press the header's Next Hand and it is still hand 6,
button on seat 3, no confirmation asked.

The mechanism stays — a dealer does pass the button along on a hand
nobody played. The name changes. The label and its title are now read off
whether a hand is out: "Next Hand ⟳" while one is, "Move Button ⟳" when
none is, written past the dimmed-reason cache each render so they follow
the table instead of freezing on the state the page loaded in. The toast
says which of the two happened, on one line: the second line told the
dealer to press the green button the bar is already holding.

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

tests/holdem/theHeader.test.js

@@ -97,9 +97,9 @@ describe("the header is one row on a phone", () => {
     });
 
     test("and the buttons grow into that width without ever shrinking below their labels", () => {
-        // `flex: 1 1 0` would divide the row into equal thirds and squeeze "Next Hand ⟳"
-        // — 105px of text — into 99. These are `white-space: nowrap`, so what gives is
-        // the text.
+        // `flex: 1 1 0` would divide the row into equal shares: at 360px the row is 269
+        // wide, so mid-hand that is 87px each and "Next Hand ⟳" needs 89 — 73 of text and
+        // 16 of padding. These are `white-space: nowrap`, so what gives is the text.
         const rule = ruleIn(PHONE(), "#holdemHeaderActions .holdemBtn") || "";
         assert.match(rule, /flex:\s*1\s+1\s+auto/, "an auto basis makes the label the floor");
         assert.match(rule, /white-space:\s*nowrap/);