LANTERN purge B1: delete the automation chain (Harvester/Conveyor/Fabricator)

Deletes the M7 production systems, automation components/math, authoring, 3
machine prefabs, and 6 test files (-43 tests, 459 green). Trims the automation
paths out of BaseRestoreSystem/SaveStructureScan/BuildPlaceSystem/BuildSendSystem/
HudSystem/HudTheme/StructureCatalogAuthoring/Tuning. RuntimePlacedTag (save
marker, a keeper) re-homed into StructureComponents.cs. StructureType byte codes
stay reserved.

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

Assets/_Project/Scripts/Client/Building/BuildSendSystem.cs

@@ -29,9 +29,8 @@ namespace ProjectM.Client
         {
             (UnityEngine.InputSystem.Key.B, StructureType.Turret),
             (UnityEngine.InputSystem.Key.V, StructureType.Wall),
-            (UnityEngine.InputSystem.Key.F, StructureType.Fabricator),
-            // DR-042 C6d: Pylon/Harvester/Conveyor are dead (unwired automation) — dropped from the hotkey fallback
-            // to match the hidden build palette; their PlaceStructure execute_code statics remain for dev.
+            // LANTERN purge: the automation buildables (Fabricator/Harvester/Conveyor) are deleted; Pylon stays
+            // hidden from the hotkey fallback to match the build palette. PlaceStructure execute_code statics remain.
         };
 
         UnityEngine.Camera _camera;   // cursor -> ground re-raycast for click-to-place (resolved lazily)
@@ -61,9 +60,6 @@ namespace ProjectM.Client
         /// <summary>EDITOR / execute_code hook: queue a wall placement at a specific cell.</summary>
         public static void PlaceWall(int cellX, int cellZ) => PlaceStructure(StructureType.Wall, cellX, cellZ);
 
-        /// <summary>EDITOR / execute_code hook: queue a fabricator placement at a specific cell.</summary>
-        public static void PlaceFabricator(int cellX, int cellZ) => PlaceStructure(StructureType.Fabricator, cellX, cellZ);
-
 #endif
 
         protected override void OnCreate()