Add blood decals, gore, mobile HUD, web start gate + touch/perf tests

Remove tools/fstest.html scratch page used to probe browser
fullscreen/orientation APIs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EznnY8rH2dXhtono1kwsXg

tests/blood_decals_test.gd

@@ -0,0 +1,97 @@
+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)