Add starter RV progression and fishing feedback

world/regions/starter_island_region.gd

@@ -11,6 +11,9 @@ const PlayerStorageInteractionType = preload(
 const DecorShopInteractionType = preload(
 	"res://world/decor_shop_interaction.gd"
 )
+const RVUpgradeInteractionType = preload(
+	"res://world/rv_upgrade_interaction.gd"
+)
 const FOLIAGE_WIND_SHADER: Shader = preload(
 	"res://world/materials/foliage_wind.gdshader"
 )
@@ -56,6 +59,10 @@ var player_storage_path: NodePath = (
 var decor_shop_path: NodePath = (
 	^"Interactables/DecorShopWorld/InteractionArea"
 )
+@export_node_path("Area3D")
+var rv_upgrade_shop_path: NodePath = (
+	^"Interactables/RVUpgradeShopWorld/InteractionArea"
+)
 @export_group("Terrain Collision")
 # The imported GLB is the collision authority. Rebuild once per region load so
 # newly authored terrain and props cannot retain a stale saved fallback shape.
@@ -95,6 +102,10 @@ func get_decor_shop() -> DecorShopInteractionType:
 	return get_node_or_null(decor_shop_path) as DecorShopInteractionType
 
 
+func get_rv_upgrade_shop() -> RVUpgradeInteractionType:
+	return get_node_or_null(rv_upgrade_shop_path) as RVUpgradeInteractionType
+
+
 func get_saltwater_shoreline_mesh() -> MeshInstance3D:
 	return get_node_or_null(^"ShorelineRibbons/Ocean") as MeshInstance3D
 
@@ -150,6 +161,7 @@ func get_spawn_surface_triangles(
 	material_names: Array[StringName],
 	minimum_global_y: float,
 	minimum_up_dot: float = 0.6,
+	maximum_global_y: float = 100.0,
 ) -> Array[PackedVector3Array]:
 	var triangles: Array[PackedVector3Array] = []
 	if material_names.is_empty():
@@ -188,6 +200,7 @@ func get_spawn_surface_triangles(
 						vertices[vertex_index + 2],
 						minimum_global_y,
 						minimum_up_dot,
+						maximum_global_y,
 					)
 			else:
 				for index_offset: int in range(0, indices.size() - 2, 3):
@@ -199,6 +212,7 @@ func get_spawn_surface_triangles(
 						vertices[indices[index_offset + 2]],
 						minimum_global_y,
 						minimum_up_dot,
+						maximum_global_y,
 					)
 	return triangles
 
@@ -211,14 +225,14 @@ func _append_spawn_triangle(
 	local_c: Vector3,
 	minimum_global_y: float,
 	minimum_up_dot: float,
+	maximum_global_y: float,
 ) -> void:
 	var a: Vector3 = mesh_instance.to_global(local_a)
 	var b: Vector3 = mesh_instance.to_global(local_b)
 	var c: Vector3 = mesh_instance.to_global(local_c)
 	if (
-		a.y <= minimum_global_y
-		or b.y <= minimum_global_y
-		or c.y <= minimum_global_y
+		maxf(a.y, maxf(b.y, c.y)) <= minimum_global_y
+		or minf(a.y, minf(b.y, c.y)) >= maximum_global_y
 	):
 		return
 	var cross: Vector3 = (b - a).cross(c - a)

world/regions/world_region.gd

@@ -22,6 +22,10 @@ func get_decor_shop() -> DecorShopInteraction:
 	return null
 
 
+func get_rv_upgrade_shop() -> RVUpgradeInteraction:
+	return null
+
+
 func get_player_storage() -> PlayerStorageInteraction:
 	return null
 
@@ -42,10 +46,24 @@ func get_spawn_surface_triangles(
 	_material_names: Array[StringName],
 	_minimum_global_y: float,
 	_minimum_up_dot: float = 0.6,
+	_maximum_global_y: float = 100.0,
 ) -> Array[PackedVector3Array]:
 	return []
 
 
+func get_saltwater_surface_height() -> float:
+	for water_region: FishableWaterRegion in get_fishable_water_regions():
+		if water_region.water_type == WaterType.Type.SALT_WATER:
+			return water_region.get_surface_height()
+	return NAN
+
+
+## Authored regions are assumed to expose only deliberately reachable home
+## sites. Procedural regions override this to reject isolated elevations.
+func is_home_exterior_position_accessible(_position: Vector3) -> bool:
+	return true
+
+
 func get_fishable_water_regions() -> Array[FishableWaterRegion]:
 	var regions: Array[FishableWaterRegion] = []
 	var root: Node = get_node_or_null(fishable_water_root)