Initial commit: Transcience MVP

Top-down twin-stick bullet-hell, Godot 4.7, server-authoritative dedicated
server with client-side prediction. Clients send input only; the server
resolves every hit for both players and enemies (no PvP).

- SimWorld: whole simulation as plain RefCounted objects (no nodes, no
  physics server), ~0.24ms/tick at peak load -- runs headless for free and
  drives 78 tests in under a second
- BulletPool: struct-of-arrays bullet storage, replicated as spawn/despawn
  events rather than per-tick state
- Emitter framework (Ring/AimedSpread/WallGap/ArcSweep) shared by trash
  enemies and bosses -- a new boss is data in src/content/content.gd, no
  simulation changes
- The Warden of the Fold: stationary 4-phase boss built entirely on that
  format
- Lobby hub with a portal into on-demand dungeon instances; one process
  hosts the hub plus every concurrent dungeon
- Emergency escape: 3s server-owned channel, cancelled by damage
- tools/check.sh, test.sh (GUT), smoke.sh (real server + bot clients over
  ENet), bench.gd; git hooks wired to the same scripts
- docs/ARCHITECTURE.md, NETCODE.md, WORKFLOW.md, ROADMAP.md

addons/gut/gui/RunAtCursor.tscn

@@ -0,0 +1,60 @@
+[gd_scene load_steps=3 format=3 uid="uid://0yunjxtaa8iw"]
+
+[ext_resource type="Script" uid="uid://c4gmgdl1xwflw" path="res://addons/gut/gui/RunAtCursor.gd" id="1"]
+[ext_resource type="Texture2D" uid="uid://6wra5rxmfsrl" path="res://addons/gut/gui/arrow.png" id="3"]
+
+[node name="RunAtCursor" type="Control"]
+custom_minimum_size = Vector2(510, 0)
+layout_mode = 3
+anchors_preset = 15
+anchor_right = 1.0
+anchor_bottom = 1.0
+offset_right = 1.0
+offset_bottom = -527.0
+grow_horizontal = 2
+grow_vertical = 2
+size_flags_horizontal = 3
+size_flags_vertical = 3
+script = ExtResource("1")
+
+[node name="HBox" type="HBoxContainer" parent="."]
+layout_mode = 0
+anchor_right = 1.0
+anchor_bottom = 1.0
+size_flags_horizontal = 3
+size_flags_vertical = 3
+
+[node name="LblNoneSelected" type="Label" parent="HBox"]
+visible = false
+layout_mode = 2
+text = "<None>"
+
+[node name="BtnRunScript" type="Button" parent="HBox"]
+layout_mode = 2
+text = "test_test.gd"
+
+[node name="Arrow1" type="TextureButton" parent="HBox"]
+custom_minimum_size = Vector2(24, 0)
+layout_mode = 2
+texture_normal = ExtResource("3")
+stretch_mode = 3
+
+[node name="BtnRunInnerClass" type="Button" parent="HBox"]
+layout_mode = 2
+tooltip_text = "Run all tests in Inner-Test-Class TestAssertNe"
+text = "TestAssertNe"
+
+[node name="Arrow2" type="TextureButton" parent="HBox"]
+custom_minimum_size = Vector2(24, 0)
+layout_mode = 2
+texture_normal = ExtResource("3")
+stretch_mode = 3
+
+[node name="BtnRunMethod" type="Button" parent="HBox"]
+layout_mode = 2
+tooltip_text = "Run test test_fails_with_integers_equal"
+text = "test_fails_with_integers_equal"
+
+[connection signal="pressed" from="HBox/BtnRunScript" to="." method="_on_BtnRunScript_pressed"]
+[connection signal="pressed" from="HBox/BtnRunInnerClass" to="." method="_on_BtnRunInnerClass_pressed"]
+[connection signal="pressed" from="HBox/BtnRunMethod" to="." method="_on_BtnRunMethod_pressed"]