Add briscola chiamata

Five-player briscola with a descending calling auction and a secret
partner. Starting with the player after the dealer, each player bids a
lower rank (A > 3 > K > H > J > 7 > 6 > 5 > 4 > 2) or passes; once the
standing bid is the two the auction continues on points (62, 64, ...).
The last player standing must bid, and the winner names any card of the
won rank: its holder is the secret partner, or the caller plays alone
when it is one of their own cards, and its suit becomes the trump. The
calling side must reach 61 (or the raised target); a 60-60 deal with the
plain target is a patta and is replayed. A match is a single deal, so
the caller and partner (or the lone caller) against the other players
map onto the platform's two-team result, Elo and match history.

The rules live in tavolo.briscola.chiamata with the
BriscolaChiamataEngine adapter registered alongside the other briscola
variants; the partner's role and the side totals stay hidden until the
called card is played. The web client gets a five-seat table, the
auction panel with legal bids and point raises, the call picker, the
reveal bands and a chiamata-aware final summary.

README.md

@@ -1,9 +1,10 @@
 # tavolo
 
-A platform for multiplayer card games. Two games are included:
+A platform for multiplayer card games. Three games are included:
 **scopone scientifico** — the four-player, fixed-partnership Italian card
-game — and **briscola**, in its classic two-player and four-player
-partnership (*briscola a quattro*) variants:
+game — **briscola**, in its classic two-player and four-player
+partnership (*briscola a quattro*) variants, and **briscola chiamata** —
+the five-player variant with a calling auction and a secret partner:
 
 - **`server/`** — backend: Python + [kaya](https://github.com/woggioni/kaya)
   framework, OIDC login, live games in Redis, match statistics in Postgres.
@@ -45,7 +46,9 @@ pigliatutto when enabled), briscola players see the deal's points and any
 *patta*; both see the running totals and must click "Understood" before
 the next hand is dealt. If someone is away the next hand is dealt
 automatically after `HAND_ACK_TIMEOUT_SECONDS` (default 30s). The
-match-ending hand is explained on the final screen.
+match-ending hand is explained on the final screen. Briscola chiamata
+plays a single deal per match, so it goes straight from the last trick to
+the final scoring screen; a 60–60 *patta* is replayed immediately.
 
 ## On your turn
 
@@ -53,12 +56,17 @@ 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).
 
 ## Watching
 
 Anyone who has the game URL (`/game/<id>`) can watch, logged in or not:
 spectators see the table, the score and every player's captured cards
-(and scope for scopone), but never a hand and never the join code. The
+(and scope for scopone), but never a hand and never the join code. In
+briscola chiamata they also see no role labels and no side totals until
+the called card is played, so the secret partner stays secret. The
 "Copy watch link" button in the waiting room and in the game HUD copies
 the URL to share. A spectator who opens the URL before the match starts
 sees a "game not started yet" waiting room.