Slice 3: Expedition Combat Spine — epoch-seeded zone waves (DR-040)

Reactivate the dormant Expedition region as a procedural combat venue.
v1 loop: walk the gate -> fight an epoch-seeded enemy wave in the
expedition -> clear -> return -> flat Ore reward (once per epoch) ->
escalated retaliation base siege.

- New sim types: ZoneEnemyTag, ZoneEnemyDirector (+ ZoneEnemyPrefab
  buffer), ZoneEnemyState, ZoneEnemyMath (grunt->charger composition
  by epoch). ZoneEnemyDirectorSystem (server, Burst): drip-spawns the
  wave at a deterministic ring under a MaxAlive cap while a player is
  out and the base is Calm; marks ClearedThisEpoch on a real clear.
  [UpdateAfter(ExpeditionFieldSystem)] only (avoids a sort cycle).
- BLOCKER 1: EnemyAISystem region-filters target selection (player +
  structure snapshots gain parallel region lists; no base structures /
  no Core fallback for expedition husks).
- BLOCKER 3: WaveSystem, ThreatDirectorSystem timeout cull, and
  CyclePhaseSystem DefendCleared + Core-breach cull all count/cull
  RegionTag{Base} husks only (the breach cull was caught region-blind
  by the post-impl review: a base breach wiped the live expedition
  wave and spuriously paid the reward).
- BLOCKER 4: reward de-duped via CycleRuntime.LastRewardedEpoch +
  ClearedThisEpoch; ExpeditionGateSystem deposits RewardOre once/epoch.
- ExpeditionFieldSystem teardown also culls zone enemies + region-
  guards the clutter loop. Subscene wired with the director + roster.

368/368 EditMode green + clean netcode Play smoke. Docs: DR-040 ->
built, session log, CLAUDE.md cross-region tag-reaudit rule.

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

Assets/_Project/Scripts/Simulation/World/CycleComponents.cs

@@ -76,5 +76,11 @@ namespace ProjectM.Simulation
 
         /// <summary>Previous-tick expedition occupancy (1 = at least one player out), for the empty&lt;-&gt;occupied edge.</summary>
         public byte PrevExpeditionOccupied;
+
+        /// <summary>The <see cref="ExpeditionEpoch"/> a zone-clear Ore reward was last banked for — gates the once-per-epoch reward so two same-tick co-op returners pay once and gate re-entry can't farm (int equality, never tick math).</summary>
+        public int LastRewardedEpoch;
+
+        /// <summary>1 once the current epoch's expedition wave has FULLY spawned and been cleared to zero live zone enemies; reset to 0 on the empty-&gt;occupied epoch bump. The reward fires only on a REAL clear.</summary>
+        public byte ClearedThisEpoch;
     }
 }