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.

scripts/rooms/floor.gd

@@ -0,0 +1,92 @@
+extends Node2D
+
+# ---------------------------------------------------------------------------
+# Constants
+# ---------------------------------------------------------------------------
+const ROOM_SCENE      = preload("res://scenes/run/rooms/room_base.tscn")
+const ROOM_W          := 960.0
+const ROOM_H          := 540.0
+const TRANSITION_TIME := 0.25
+const ENTRY_INSET     := 60.0    # how far from wall edge the player appears
+
+# ---------------------------------------------------------------------------
+# Node refs
+# ---------------------------------------------------------------------------
+@onready var rooms_container: Node2D   = $Rooms
+@onready var camera:          Camera2D = $Camera2D
+@onready var player:          Node2D   = $Player
+
+# ---------------------------------------------------------------------------
+# State
+# ---------------------------------------------------------------------------
+var _rooms:           Dictionary = {}   # Vector2i -> Room
+var _current_grid:    Vector2i
+var _transitioning:   bool = false
+
+# ---------------------------------------------------------------------------
+# Boot
+# ---------------------------------------------------------------------------
+func _ready() -> void:
+	var floor_num: int = max(RunManager.current_floor, 1)
+	_build_floor(FloorGenerator.generate(floor_num))
+
+
+func _build_floor(floor_data: Array) -> void:
+	var start_pos := Vector2i.ZERO
+
+	for room_data in floor_data:
+		var room_node: Room = ROOM_SCENE.instantiate()
+		room_node.position = _grid_to_world(room_data.grid_pos)
+		rooms_container.add_child(room_node)
+		room_node.setup(room_data, self)
+		_rooms[room_data.grid_pos] = room_node
+
+		if room_data.type == RoomData.RoomType.START:
+			start_pos = room_data.grid_pos
+
+	# Snap camera + player to start room
+	var world_start := _grid_to_world(start_pos)
+	camera.position        = world_start
+	player.global_position = world_start
+	_current_grid          = start_pos
+	_rooms[start_pos].activate()
+
+# ---------------------------------------------------------------------------
+# Transitions
+# ---------------------------------------------------------------------------
+func transition_to(target_grid: Vector2i, from_direction: String) -> void:
+	if _transitioning:
+		return
+	_transitioning    = true
+	_current_grid     = target_grid
+
+	var new_world := _grid_to_world(target_grid)
+
+	# Teleport player to the entry side of the new room immediately
+	player.global_position = new_world + _entry_offset(from_direction)
+
+	# Activate the room (may spawn enemies) — we're outside physics here
+	_rooms[target_grid].activate()
+
+	# Slide the camera
+	var tween := create_tween()
+	tween.tween_property(camera, "position", new_world, TRANSITION_TIME)
+	tween.tween_callback(func(): _transitioning = false)
+
+
+func _entry_offset(from_direction: String) -> Vector2:
+	# Player exits through `from_direction`; they enter the new room
+	# from the opposite side.
+	var i := ENTRY_INSET
+	match from_direction:
+		"up":    return Vector2(0,    ROOM_H / 2.0 - i)   # enter at bottom
+		"down":  return Vector2(0,   -ROOM_H / 2.0 + i)   # enter at top
+		"left":  return Vector2( ROOM_W / 2.0 - i, 0)     # enter at right
+		"right": return Vector2(-ROOM_W / 2.0 + i, 0)     # enter at left
+	return Vector2.ZERO
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+func _grid_to_world(grid_pos: Vector2i) -> Vector2:
+	return Vector2(grid_pos.x * ROOM_W, grid_pos.y * ROOM_H)