feat(battle-node): Bot dispatch arms in ComputeFrames

Three new arms gated on Type == BattleType.Bot, placed before the
existing PvP / Scripted arms:
- InitBattle → ack to sender (no Matched push — client uses AIBattleStart HTTP data)
- Loaded → silent (no BattleStart, no Deal — client short-circuits to GotoBattle)
- TurnEnd / TurnEndFinal → Judge to sender only (not broadcast)

Other URIs in Bot mode fall through existing arms: Swap is Type-agnostic
(per-sender SwapResponse + Ready), Retire/Kill hits the existing
Scripted no-contest BattleFinish(Win), gameplay forwarders are gated on
Pvp so Bot's PlayActions/Echo/etc. fall through default (drop). 8 new
dispatch tests cover the wire contract.

Reference: docs/api-spec/in-battle/ai-passive.md.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

SVSim.BattleNode/Sessions/BattleSession.cs

@@ -135,6 +135,38 @@ public sealed class BattleSession
                 phaseFrom!.Phase = BattleSessionPhase.AwaitingInitBattle;
                 break;
 
+            // --- Phase 3 Bot arms — placed BEFORE the existing handshake arms so they
+            // win pattern matching on Type == Bot. Bot mode: ack handshake, silent Loaded,
+            // Judge-to-sender on TurnEnd. The rest reuse Scripted's arms (Retire/Kill ->
+            // BattleFinishNoContest, Swap -> per-sender response, default -> drop).
+            // Reference: docs/api-spec/in-battle/ai-passive.md.
+
+            case NetworkBattleUri.InitBattle
+                when Type == BattleType.Bot && phaseFrom?.Phase == BattleSessionPhase.AwaitingInitBattle:
+                // Ack only — NO Matched push. Client uses AIBattleStart HTTP data for
+                // the lobby plates instead of the Matched envelope.
+                result.Add((from, BuildAck(NetworkBattleUri.InitBattle), true));
+                phaseFrom!.Phase = BattleSessionPhase.AwaitingLoaded;
+                break;
+
+            case NetworkBattleUri.Loaded
+                when Type == BattleType.Bot && phaseFrom?.Phase == BattleSessionPhase.AwaitingLoaded:
+                // Silent — no BattleStart, no Deal. Client's AINetworkBattleManager
+                // short-circuits to its local AI flow after Loaded; the server has
+                // nothing to contribute.
+                phaseFrom!.Phase = BattleSessionPhase.AwaitingSwap;
+                break;
+
+            case NetworkBattleUri.TurnEnd
+                when Type == BattleType.Bot && phaseFrom?.Phase == BattleSessionPhase.AfterReady:
+            case NetworkBattleUri.TurnEndFinal
+                when Type == BattleType.Bot && phaseFrom?.Phase == BattleSessionPhase.AfterReady:
+                // Judge to sender ONLY (not broadcast — there's no real other side).
+                // The client's JudgeOperation → ControlTurnStartPlayer flips back to
+                // the local AI's turn after this Judge arrives.
+                result.Add((from, BuildJudgeBroadcast(), false));
+                break;
+
             case NetworkBattleUri.InitBattle when phaseFrom?.Phase == BattleSessionPhase.AwaitingInitBattle:
                 // Phase 1: push Matched only to the "real" participant. The session reads
                 // selfInfo from from.Context and oppoInfo from other.Context (the scripted