Initial commit — Station 0 vertical slice in progress

Includes full design documentation (ARCHITECTURE, DESIGN_NOTES, CONTENT_SPEC, PRODUCTION_NOTES)
and active Godot 4 / GDScript codebase. Core systems built: player, floor generation,
room system, enemy base, body part upgrades, run manager, save system, HUD, EventBus.

scenes/items/run_item_pickup.tscn

@@ -0,0 +1,14 @@
+[gd_scene load_steps=3 format=3]
+
+[ext_resource type="Script" path="res://scripts/items/run_item_pickup.gd" id="1"]
+
+[sub_resource type="CircleShape2D" id="1"]
+radius = 20.0
+
+[node name="RunItemPickup" type="Area2D"]
+script = ExtResource("1")
+collision_layer = 0
+collision_mask = 2
+
+[node name="CollisionShape2D" type="CollisionShape2D" parent="."]
+shape = SubResource("1")