fix(scene): persist scene only after the client actually moves

The user's save was bricked by teleporting to entry 100000304: the client
offers it in the map but NREs in AdventurePhase._EnterStep1_InitializeMapInfo
while loading, and the server had already saved that scene - every login
then replayed the broken scene (stuck on the train-window loading screen).

- loadScene no longer calls SavePersistent; SceneEntityMove's 5s cadence
  persists the scene only once the client walks in it (the existing arena
  guard already kept challenge scenes out of the save)
- reset persistent to entry 102020107 (proven walkable in the 01:00/01:38
  sessions)

persistent

@@ -6,15 +6,15 @@
     "3": 1004
   },
   "position": {
-    "x": 5379,
-    "y": 0,
-    "z": -2300,
-    "rot_y": 54387
+    "x": -92,
+    "y": 4278,
+    "z": 68083,
+    "rot_y": 155566
   },
   "scene": {
-    "plane_id": 10000,
-    "floor_id": 10000000,
-    "entry_id": 100000304
+    "plane_id": 10202,
+    "floor_id": 10202001,
+    "entry_id": 102020107
   },
   "main_character": "FemaleHarmony",
   "march_type": "MarchHunt",