feat(world): generic dive site scene fed by a baked site definition

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

content/sites/vehicle_test.tres

@@ -0,0 +1,28 @@
+[gd_resource type="Resource" script_class="DiveSiteDefinition" format=3]
+
+[ext_resource type="Script" path="res://game/domain/sites/site_placement.gd" id="1_j2ii4"]
+[ext_resource type="Script" path="res://game/domain/sites/site_route.gd" id="2_tj3be"]
+[ext_resource type="Script" path="res://game/domain/sites/dive_site_definition.gd" id="3_usfet"]
+[ext_resource type="Resource" path="res://content/sites/vehicle_test_terrain.res" id="4_awe7g"]
+
+[sub_resource type="Resource" id="Resource_5juth"]
+script = ExtResource("1_j2ii4")
+placement_id = &"calibration_target"
+kind = 1
+position_m = Vector3(0, -60.44367, -58)
+footprint_m = Vector3(8, 5, 7)
+
+[sub_resource type="Resource" id="Resource_tboiu"]
+script = ExtResource("1_j2ii4")
+placement_id = &"navigation_beacon"
+kind = 5
+position_m = Vector3(0, -15, -22)
+
+[resource]
+script = ExtResource("3_usfet")
+site_id = &"vehicle_test"
+display_name = "Site de calibration du véhicule"
+terrain = ExtResource("4_awe7g")
+playable_bounds_m = Rect2(-90, -176, 180, 204)
+spawn_position_m = Vector3(0, -12, 12)
+placements = Array[ExtResource("1_j2ii4")]([SubResource("Resource_5juth"), SubResource("Resource_tboiu")])