Add briscola: classic two-player and briscola a quattro

New tavolo-briscola distribution implementing briscola on the platform:

- pure rules (state.py, engine.py): 3-card deals, a face-up trump that
  is the last card drawn, trump-first trick resolution (A > 3 > K > H >
  J > 7 > 6 > 5 > 4 > 2), 120 points per deal, 60-60 patta re-deals, a
  configurable target score (default 61), deal-end acknowledgements and
  turn auto-play;
- BriscolaEngine (briscola, 2 players) and BriscolaQuattroEngine
  (briscola_a_quattro, 4 players in fixed partnerships) adapters;
- registered in tavolo-app, packaged in the Docker image, documented.

Platform fixes surfaced by a two-player lobby:

- the websocket state and snapshot payloads now carry seats_open (they
  were only in the REST lobby payload), so lobbies with player counts
  other than four render correctly; seats_open is clamped at zero;
- the web client logs unparseable server messages instead of silently
  dropping them.

Web client: briscola table for both variants (stock, face-up trump,
trick, last-trick banner), deal summary modal and game-over overlay.

Tests: tavolo-briscola rules/adapter suites, app integration tests
(lobby, websocket play, turn timeout, deal-end acks, persistence), a
platform seats_open test and frontend model parsing tests.

server/packages/tavolo-app/README.md

@@ -2,14 +2,15 @@
 
 The deployable tavolo application: the composition root wiring
 [`tavolo-platform`](../tavolo-platform/README.md) to the
-[`tavolo-scopone`](../tavolo-scopone/README.md) game.
+[`tavolo-scopone`](../tavolo-scopone/README.md) and
+[`tavolo-briscola`](../tavolo-briscola/README.md) games.
 
 ## Contents
 
 - `app.py` — assembles the `KayaApp` (session/OIDC/Tortoise/OpenAPI
   mixins plus `PlatformMixin` and the deadline scheduler), registers the
-  `ScoponeEngine` with its configured timeouts, and exposes
-  `tavolo.app:app` for granian.
+  `ScoponeEngine`, `BriscolaEngine` and `BriscolaQuattroEngine` with
+  their configured timeouts, and exposes `tavolo.app:app` for granian.
 - `config.py` — environment-driven frozen `Settings`.
 - `telemetry.py` — the optional OpenTelemetry wiring beyond kaya-otel:
   meter/tracer/logger providers, the

server/packages/tavolo-app/pyproject.toml

@@ -5,12 +5,13 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "tavolo-app"
 version = "0.1.0"
-description = "Tavolo multiplayer card-game application: platform + scopone game wiring"
+description = "Tavolo multiplayer card-game application: platform + games wiring"
 readme = "README.md"
 requires-python = ">=3.10"
 dependencies = [
     "tavolo-platform",
     "tavolo-scopone",
+    "tavolo-briscola",
     "kaya-core",
     "kaya-cors",
     "kaya-session",

server/packages/tavolo-app/src/tavolo/app.py

@@ -39,6 +39,7 @@ from kaya.oidc import OIDCConfig, OIDCProviders
 from kaya.openapi import OpenAPIMixin
 from kaya.session import SessionMixin
 from redis.asyncio import Redis
+from tavolo.briscola import BriscolaEngine, BriscolaQuattroEngine
 from tavolo.platform import GameRegistry, Platform, PlatformMixin
 from tavolo.platform.deadlines import DeadlineScheduler, DeadlineSchedulerMixin
 from tavolo.platform.store import GameStore, InMemoryGameStore, RedisGameStore
@@ -131,9 +132,21 @@ registry.register(
         hand_ack_timeout_seconds=settings.hand_ack_timeout_seconds,
     )
 )
+registry.register(
+    BriscolaEngine(
+        turn_timeout_seconds=settings.turn_timeout_seconds,
+        hand_ack_timeout_seconds=settings.hand_ack_timeout_seconds,
+    )
+)
+registry.register(
+    BriscolaQuattroEngine(
+        turn_timeout_seconds=settings.turn_timeout_seconds,
+        hand_ack_timeout_seconds=settings.hand_ack_timeout_seconds,
+    )
+)
 log.info("registered games: %s", ", ".join(e.id for e in registry.all()))
 log.debug(
-    "scopone timeouts: hand_ack=%ds turn=%ds",
+    "game timeouts: hand_ack=%ds turn=%ds",
     settings.hand_ack_timeout_seconds,
     settings.turn_timeout_seconds,
 )

server/packages/tavolo-app/src/tavolo/config.py

@@ -215,12 +215,12 @@ class Settings:
     # are served by Granian under /static (GRANIAN_STATIC_PATH_* env vars).
     static_dir: str
     # Seconds the between-hands scoring summary waits for acknowledgements
-    # before dealing the next hand anyway (wired into the ScoponeEngine;
+    # before dealing the next hand anyway (wired into the game engines;
     # see tavolo.app).
     hand_ack_timeout_seconds: int
     # Seconds a player has to play before the server plays a random legal
     # card for them, covering disconnects and idle players (wired into the
-    # ScoponeEngine; see tavolo.app).
+    # game engines; see tavolo.app).
     turn_timeout_seconds: int
     # Upper bound on how long the deadline consumer sleeps between polls
     # when nothing else wakes it. Enqueued deadlines are announced over a