refactor(battle-node): remove ScriptedBotParticipant and dev-affordance wiring

Deletes the scripted opponent and every entry point that created a
BattleType.Scripted session (the ?scripted=1 query opt-in, the
SoloDefaultsToScripted toggle, the resolver short-circuit, the WS handler case,
the bridge validation arm). Real two-client PvP and the Bot matchmaking-timeout
fallback are untouched. ResolveAsync drops its scriptedOptIn parameter.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.BattleNode/Bridge/BattleNodeOptions.cs

@@ -16,17 +16,6 @@ public sealed class BattleNodeOptions
     /// </summary>
     public TimeSpan WaitingRoomTimeout { get; set; } = TimeSpan.FromSeconds(60);
 
-    /// <summary>
-    /// Dev convenience: when true, matchmaking endpoints that would otherwise park
-    /// a solo poller (returning 3002 RETRY until a partner arrives) instead return
-    /// a Scripted match immediately — equivalent to passing <c>?scripted=1</c> on
-    /// every request. Turn off to test real PvP with two clients. Default false.
-    /// <para>Trade-off: while on, two viewers polling simultaneously each get
-    /// their own Scripted match instead of pairing with each other. Toggling off
-    /// is the only way to get PvP behavior.</para>
-    /// </summary>
-    public bool SoloDefaultsToScripted { get; set; } = false;
-
     /// <summary>
     /// When true, <see cref="Sessions.Participants.RealParticipant"/> emits per-frame
     /// diagnostic logs at Information level: <c>[sio-in]</c> on every inbound msg/alive/hand