feat(slice2): TeleportArrivalRules.Decide — outdoor holds until landblock loaded (#145 §3.4)

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

src/AcDream.App/World/TeleportArrivalController.cs

@@ -116,29 +116,29 @@ public static class TeleportArrivalRules
     /// <param name="claimUnhydratable">The destination cell can never hydrate.</param>
     /// <param name="indoor">Destination is an indoor cell (cell index ≥ 0x0100).</param>
     /// <param name="indoorCellReady">For an indoor destination, the EnvCell floor has hydrated.</param>
+    /// <param name="outdoorReady">For an outdoor destination, the physics landblock is loaded
+    ///     (<see cref="AcDream.Core.Physics.PhysicsEngine.IsLandblockLoaded"/> returned true for the
+    ///     destination landblock id). Ignored for indoor destinations.</param>
     public static ArrivalReadiness Decide(
         bool claimUnhydratable,
         bool indoor,
-        bool indoorCellReady)
+        bool indoorCellReady,
+        bool outdoorReady)
     {
         if (claimUnhydratable)
             return ArrivalReadiness.Impossible;
 
         // Indoor (sealed dungeon / building interior): gate on the EnvCell floor hydrating,
-        // exactly as #135. The dungeon-IN path pre-collapses + waits for the cell struct, and
-        // its placement validates the specific claimed cell (the indoor resolve is cell-keyed,
-        // not the grid-snap), so it is unaffected by the overlap that broke teleport-OUT.
+        // exactly as #135. Unaffected by the outdoor-landblock gate.
         if (indoor)
             return indoorCellReady ? ArrivalReadiness.Ready : ArrivalReadiness.NotReady;
 
-        // Outdoor: place IMMEDIATELY on the server-authoritative position. #145/#138 — holding
-        // for the destination to stream in is futile: streaming does NOT progress while the
-        // player is held in PortalSpace (the destination only loads once placement flips the
-        // state to InWorld). The stale source center landblock is dropped at recenter (see
-        // GameWindow.OnLivePositionUpdated), so the arrival resolve falls through to the
-        // server-authoritative cell/position (Resolve NO-LANDBLOCK verbatim) and the player is
-        // placed grounded there; streaming then loads the destination and the per-frame resolve
-        // grounds onto it. This trusts the server's teleport position — retail-faithful.
-        return ArrivalReadiness.Ready;
+        // Outdoor (#145 §3.4): hold until the physics landblock is registered.
+        // AddLandblock is atomic (terrain + cells + portals in one write — PhysicsEngine.cs:70),
+        // so ContainsKey implies the collision mesh is present and resolvable. The hold is
+        // self-resolving: streaming progresses unconditionally during the hold because the
+        // streaming controller runs before TeleportArrivalController.Tick (GameWindow.cs:7420-7551).
+        // The 10 s timeout safety-net (_maxHoldFrames) remains active.
+        return outdoorReady ? ArrivalReadiness.Ready : ArrivalReadiness.NotReady;
     }
 }