Use player names in two-player briscola

Classic briscola has no partnerships: its "teams" are just the two
players, but the UI labelled them Team A/Team B.

- add is_individual_game() and GameView::player_name_for_team() to the
  model;
- the briscola table HUD reads "Alice 0 — 0 Bob (target 61)" and the
  seat panels drop the Team badge for two-player games;
- the deal summary and game-over screen name the sides and the winner;
- the waiting room and join preview hide the Team badge.

briscola a quattro and scopone keep their team labels, and the match
history table is unchanged.

web/src/model.rs

@@ -229,6 +229,18 @@ pub struct GameView {
     pub last_deal: Option<DealSummary>,
 }
 
+impl GameView {
+    /// Display name of the player on team `team` ("A"/"B"), for games
+    /// without partnerships; falls back to the team label itself.
+    pub fn player_name_for_team(&self, team: &str) -> String {
+        self.players
+            .iter()
+            .find(|p| p.team == team)
+            .map(|p| p.name.clone())
+            .unwrap_or_else(|| team.to_string())
+    }
+}
+
 #[derive(Debug, Deserialize)]
 #[serde(tag = "type", rename_all = "snake_case")]
 #[allow(dead_code)]
@@ -663,6 +675,13 @@ pub fn is_briscola(game_type: &str) -> bool {
     game_type == "briscola" || game_type == "briscola_a_quattro"
 }
 
+/// Whether a game is played by two individuals rather than partnerships
+/// (classic two-player briscola): team labels and team messages are
+/// replaced by the players' names.
+pub fn is_individual_game(game_type: &str) -> bool {
+    game_type == "briscola"
+}
+
 /// Human-readable suit name for a one-letter code (`D` -> "denari").
 pub fn suit_name(suit: &str) -> String {
     match suit {
@@ -1174,6 +1193,31 @@ mod tests {
         assert_eq!("?", suit_name("?"));
     }
 
+    #[test]
+    fn is_individual_game_only_matches_two_player_briscola() {
+        assert!(is_individual_game("briscola"));
+        assert!(!is_individual_game("briscola_a_quattro"));
+        assert!(!is_individual_game("scopone_scientifico"));
+    }
+
+    #[test]
+    fn player_name_for_team_resolves_names() {
+        let g: GameView = serde_json::from_value(json!({
+            "id": "b1",
+            "game_type": "briscola",
+            "phase": "playing",
+            "players": [
+                {"sub": "alice", "name": "Alice", "seat": 0, "team": "A"},
+                {"sub": "bob", "name": "Bob", "seat": 1, "team": "B"},
+            ],
+        }))
+        .unwrap();
+        assert_eq!("Alice", g.player_name_for_team("A"));
+        assert_eq!("Bob", g.player_name_for_team("B"));
+        // Unknown labels fall back to the label itself.
+        assert_eq!("C", g.player_name_for_team("C"));
+    }
+
     #[test]
     fn fallback_game_types_cover_the_registered_games() {
         let types = fallback_game_types();