Base<->Expedition ties: portal rooms, class-at-base, prep spend + Health.Max, C3/C4/Spitter (DR-046)

Portal-gated rooms: new RunLifecycle.RoomExplore loot window; room+nodes
persist past the last kill; PortalInteractRequest -> server-only PortalCommand
advances (client derives the portal pos). RunDirectorSystem moves teardown off
the InRoom edge, relocates the boss-branch/route-gate into the RoomExplore exit,
and advances an empty expedition immediately (incl. a boss clear).

Class-at-base via a shared ClassSwapUtil (meta-band strip + per-class
MetaTierState replay, so the base RPC and the dev SetClass can't drift);
ClassSelectRequest Staging-gated. Per-run PREP buffs (PrepPurchaseRequest,
PrepCatalog): once-per-run == the row's prep StatModifier band is present,
TotalOf-before-Withdraw atomic, stripped on Returning beside the boon band.

Health.Max promoted to [GhostField] (the one ghost-hash re-bake) so the boss +
floating enemy HP bars read it directly. Feel: melee cone connect-thunk (C3),
hit-stop throttle so a horde wipe can't stutter (C4), Spitter cornered-hold.

456/456 EditMode; two adversarial reviews (pre-code 13-confirmed folded;
post-impl clean bar the RoomExplore boss-clear dead-time, fixed).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Assets/_Project/Scripts/Simulation/Combat/ClassSelectRequest.cs

@@ -0,0 +1,16 @@
+using Unity.NetCode;
+
+namespace ProjectM.Simulation
+{
+    /// <summary>
+    /// Client → server: pick the player's class at base. Server honors it ONLY in <c>RunInfo.Lifecycle==Staging</c>
+    /// and applies the FULL swap via <see cref="ClassSwapUtil"/> (class seeds + permanent-meta re-sync + AbilityRef +
+    /// cooldown reset + heal/clamp) — a partial swap would mis-set the meta record + Max HP (DR-046 review). The class
+    /// is server-authoritative + re-validated, so a forged/stale request is simply dropped. UNCONDITIONAL wire type.
+    /// </summary>
+    public struct ClassSelectRequest : IRpcCommand
+    {
+        /// <summary>Requested class id (0/unknown → Warrior via ClassTraits.Normalize).</summary>
+        public byte ClassId;
+    }
+}