fix(phys): #107 gate-run regression — auto-entry hold opened on a mid-population cache read; wait for the claimed cell itself

Gate-run finding (wedge-107-gate-indoor-login.log + dat scan): ACE saved the
cell one room off (claim 0xA9B40172, position inside 0xA9B40171 — adjacent
rooms). FindVisibleChildCell corrects this fine when hydrated (proven by the
new AdjacentRoomClaim regression test), but the live entry committed the raw
claim: IsSpawnCellReady's "any cell struct in the landblock => claim is bogus,
proceed" disambiguator observed the MID-POPULATION state (interiors hydrate in
id order on the background worker; the render-thread predicate read the cache
mid-loop) and opened the gate before the claim and its stab neighbors were
cached. AdjustPosition then saw a null cell struct and silently passed the
claim through; the first movement demoted the player to outdoor inside the
house — the user-visible "transparent interior, see straight through walls"
(render is downstream of membership: an outdoor-classified viewer only sees
the interior through the doorway flood).

Fix: the hold now waits for THE CLAIMED CELL's struct, full stop
(IsSpawnCellReady simplification; HasAnyCellStructInLandblock removed).
Claims that can never hydrate are filtered by GameWindow against the dat's
LandBlockInfo.NumCells range (memoized IsSpawnClaimUnhydratable), and
PhysicsEngine.Resolve carries a loud lost-cell-equivalent safety net: an
indoor claim with NO cell struct AND NO CellSurface floor data demotes to the
outdoor landcell with a [spawn-adjust] line instead of committing raw
(retail GotoLostCell :283418; documented divergence). Partial hydration
(CellSurface present, struct pending) keeps the legacy floor-snap behavior —
HasCellSurface uses the file's masked-low-word norm so bare-id fixtures and
full-id production both resolve.

Baseline restored: Core 1381 (+4 new #107 conformance tests) + 4 pre-existing
#99-era failures + 1 skip; App 223 / UI 420 / Net 294.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Rendering/GameWindow.cs

@@ -1012,13 +1012,15 @@ public sealed class GameWindow : IDisposable
                                               // additionally waits for the claimed cell's hydration so the
                                               // entry snap's AdjustPosition validation can act (retail loads
                                               // the cell synchronously before SetPosition; this is the
-                                              // async-streaming equivalent). A claim whose landblock's
-                                              // interior batch hydrated WITHOUT it is poisoned — proceed
-                                              // and let AdjustPosition demote it.
+                                              // async-streaming equivalent). Claims that can never hydrate
+                                              // (id outside the landblock's NumCells range per the dat)
+                                              // don't hold the gate — the Resolve-head safety net demotes
+                                              // them loudly.
                                               && (!_lastSpawnByGuid.TryGetValue(_playerServerGuid, out var sp)
                                                   || sp.Position is not { } spawnClaim
                                                   || spawnClaim.LandblockId == 0
-                                                  || _physicsEngine.IsSpawnCellReady(spawnClaim.LandblockId)),
+                                                  || _physicsEngine.IsSpawnCellReady(spawnClaim.LandblockId)
+                                                  || IsSpawnClaimUnhydratable(spawnClaim.LandblockId)),
                 enterPlayerMode:         EnterPlayerModeFromAutoEntry);
         }
 
@@ -11305,6 +11307,34 @@ public sealed class GameWindow : IDisposable
     /// the guard already guarantee <c>_entitiesByServerGuid</c> contains
     /// the player guid, so the inner TryGetValue is a fast-path success.
     /// </summary>
+    // #107 (2026-06-10): memoized "this indoor spawn claim can never hydrate"
+    // check against the dat's LandBlockInfo.NumCells. Used by the auto-entry
+    // hold so a garbage claim doesn't stall login forever; the Resolve-head
+    // safety net demotes it loudly once entry proceeds.
+    private (uint Claim, bool Unhydratable)? _spawnClaimRangeMemo;
+
+    private bool IsSpawnClaimUnhydratable(uint claim)
+    {
+        if ((claim & 0xFFFFu) < 0x0100u) return false;
+        if (_spawnClaimRangeMemo is { } m && m.Claim == claim) return m.Unhydratable;
+
+        bool unhydratable = false;
+        if (_dats is not null)
+        {
+            DatReaderWriter.DBObjs.LandBlockInfo? lbInfo;
+            lock (_datLock)
+            {
+                lbInfo = _dats.Get<DatReaderWriter.DBObjs.LandBlockInfo>(
+                    (claim & 0xFFFF0000u) | 0xFFFEu);
+            }
+            uint low = claim & 0xFFFFu;
+            unhydratable = lbInfo is null || lbInfo.NumCells == 0
+                || low >= 0x0100u + lbInfo.NumCells;
+        }
+        _spawnClaimRangeMemo = (claim, unhydratable);
+        return unhydratable;
+    }
+
     private void EnterPlayerModeFromAutoEntry()
     {
         _playerMode = true;