Remove the persistent blood-decal system

Strip only the floor/wall blood-splat decals added in 981ebf1, keeping the
older death-spray, spear-wound spurt, and "Blood & Gore" toggle:

- Delete blood_decals.gd + shader, the Gore autoload (gore.gd), and
  tests/blood_decals_test.gd
- Drop the Gore autoload and the Blood DP section
- Remove all Gore.splat() call sites (matador.gd, bear.gd, player.gd);
  the _blood_burst spray and _spawn_blood spurt stay
- game_shell no longer spawns a per-level decal pool
- Update level_switch test + run_tests.sh accordingly

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CmG3mQGVXZUPDVapmdbWZ1

tests/blood_decals_test.gd

@@ -1,97 +0,0 @@
-extends SceneTree
-## Persistent blood splats (blood_decals.gd + the Gore autoload). Guards four contracts:
-##   • a splat stamps quads onto the floor and onto a wall within reach of the hit;
-##   • the ring buffer caps the instance count no matter how many hits land;
-##   • Settings.gore = false spawns nothing;
-##   • the pool is a plain node, so it frees with its parent (a level swap clears the stains).
-## blood_decals.gd references the DP autoload, so it's load()ed at runtime here (not a
-## top-level preload) — under --script a preload compiles before autoloads register.
-## Run: godot --headless --script tests/blood_decals_test.gd
-
-var _pass := 0
-var _fail := 0
-
-
-func _init() -> void:
-	_run.call_deferred()
-
-
-func _ok(c: bool, m: String) -> void:
-	if c:
-		_pass += 1
-		print("  PASS: ", m)
-	else:
-		_fail += 1
-		print("  FAIL: ", m)
-
-
-# Count instances actually placed on the map. Only the first `visible_instance_count` slots of
-# the ring buffer are drawn, so that's the live count once the buffer has wrapped.
-func _live_instances(pool: Node) -> int:
-	var mm: MultiMesh = pool.multimesh
-	if mm == null:
-		return 0
-	return mm.visible_instance_count
-
-
-func _static_box(size: Vector3, pos: Vector3) -> StaticBody3D:
-	var body := StaticBody3D.new()
-	body.collision_layer = 1  # PhysicsLayers.WORLD
-	body.position = pos
-	var shape := CollisionShape3D.new()
-	var box := BoxShape3D.new()
-	box.size = size
-	shape.shape = box
-	body.add_child(shape)
-	return body
-
-
-func _run() -> void:
-	var dp: Node = root.get_node("DP")
-	var settings: Node = root.get_node("Settings")
-	var cap := int(dp.f("blood_cap"))
-
-	# A minimal world: a floor plane and one vertical wall, both on WORLD so the splat rays hit.
-	var world := Node3D.new()
-	root.add_child(world)
-	world.add_child(_static_box(Vector3(40, 1, 40), Vector3(0, -0.5, 0)))   # floor
-	world.add_child(_static_box(Vector3(1, 6, 40), Vector3(1.4, 3, 0)))     # wall at x≈1.4
-
-	var pool: Node = (load("res://blood_decals.gd") as GDScript).new()
-	world.add_child(pool)
-	await create_timer(0.4).timeout
-
-	# Baked atlas exists and is one row of 8 shapes.
-	var atlas: Texture2D = pool.material_override.get_shader_parameter("atlas")
-	_ok(atlas != null and atlas.get_width() == 8 * 64, "splat atlas baked (8 cells)")
-
-	# A hit next to the wall stains both the floor beneath it and the wall.
-	settings.gore = true
-	pool.splat(Vector3(0.8, 0.1, 0.0), Vector3(1, 0, 0), 0.6)
-	var after_one := _live_instances(pool)
-	_ok(after_one > 0, "a splat stamps the floor (got %d quads)" % after_one)
-	# Floor cluster is 1 + satellites; anything beyond that came from the wall fan.
-	var floor_max := 1 + int(dp.f("blood_satellites"))
-	_ok(
-		after_one > floor_max,
-		"a nearby wall also catches blood (%d > floor-only %d)" % [after_one, floor_max]
-	)
-
-	# Ring buffer: hammer far past the cap; live count never exceeds it.
-	for i in cap * 2:
-		pool.splat(Vector3(0.0, 0.1, 0.0), Vector3(1, 0, 0), 0.4)
-	_ok(_live_instances(pool) <= cap, "ring buffer holds at the cap (%d)" % cap)
-
-	# Gore off: no new stains. Route through the Gore autoload to prove the gate lives there.
-	var before_off := _live_instances(pool)
-	settings.gore = false
-	root.get_node("Gore").splat(Vector3(5, 0.1, 0.0), Vector3.ZERO, 0.6)
-	_ok(_live_instances(pool) == before_off, "gore off spawns nothing")
-
-	# Lifetime: the pool is a plain node, so freeing its parent (a level swap) clears it.
-	world.queue_free()
-	await create_timer(0.2).timeout
-	_ok(not is_instance_valid(pool), "pool frees with its parent (no leak into next level)")
-
-	print("Results: %d passed, %d failed" % [_pass, _fail])
-	quit(1 if _fail > 0 else 0)

tests/blood_decals_test.gd.uid

@@ -1 +0,0 @@
-uid://b8em8poj26a57

tests/level_switch_test.gd

@@ -53,13 +53,8 @@ func _run() -> void:
 	# Shell survives and hosts exactly one level module.
 	var level_root: Node = scene.get_node_or_null("LevelRoot")
 	_ok(level_root != null, "shell has a LevelRoot")
-	# LevelRoot holds the module plus the level's blood-splat pool; exactly one of them
-	# is the geometry module (the other is BloodDecals).
-	var module_children := 0
-	if level_root != null:
-		for child: Node in level_root.get_children():
-			if not child.is_in_group(&"blood_decals"):
-				module_children += 1
+	# LevelRoot holds exactly the one level module.
+	var module_children := level_root.get_child_count() if level_root != null else 0
 	_ok(module_children == 1, "exactly one level module loaded")
 	_ok(not get_nodes_in_group(&"player").is_empty(), "player (shell) present")