Let the asso pigliatutto ace capture itself on a bare table

With the rule enabled, an ace played on an empty table goes straight to
the player's capture pile instead of staying on the table: it counts as
the last capture but never scores a scopa. An empty capture request now
matches only that self-capture option, so requesting nothing still can't
satisfy a real capture.

server/packages/tavolo-scopone/README.md

@@ -11,7 +11,7 @@ implementation.
   (de)serialization. No session envelope, no transport, no I/O.
 - `engine.py` — the pure rules engine: deck, legal captures, plays,
   auto-play, hand scoring (carte, denara, settebello, primiera, scope,
-  napola), the optional asso pigliatutto sweep, hand-end
+  napola), the optional asso pigliatutto capture, hand-end
   acknowledgements. Deterministic and I/O-free apart from logging, so the
   whole rule set is unit-testable.
 - `errors.py` — scopone-specific errors (`CardNotInHand`); every other