Make an absent chiamata bidder pass instead of bidding randomly

The auction timeout bid a random legal rank, which could hand the
auction (and the call) to a disconnected player. An absent bidder now
always passes; only the last player standing before any bid cannot
pass, and is made to bid the ace - its suit is picked at random by the
existing call timeout. This keeps a deal from stalling without a caller
while never letting an absent player outbid someone.

The deadline log line now says which of the two happened.

README.md

@@ -56,9 +56,10 @@ Every turn shows a countdown (`TURN_TIMEOUT_SECONDS`, default 30s). If a
 player does not move — disconnected or fallen asleep — the server plays a
 random legal card for them (choosing among the legal captures when the
 rules require a capture), so one absent player cannot stall the table.
-Briscola chiamata arms the same countdown for its auction bids and for
-the auction winner's called-card choice (auto-bid or auto-pass, then a
-random suit of the won rank).
+Briscola chiamata arms the same countdown for its auction turns and for
+the auction winner's called-card choice: an absent bidder passes, the
+last player standing with no bid is made to bid the ace, and a timed-out
+call names a random suit of the won rank.
 
 ## Watching