- test_level.tscn: minimal Node3D root (zero SubResource references)
- debug/test_level_builder.gd: runtime floor/walls/lighting/camera/UI
shapes/meshes created from BoxShape3D/BoxMesh — no .tscn subresources
- project.godot: revert features to 4.6 (installed build is 4.6.3)
- scenes/test_level/test_level.tscn — playable test environment (30x30 floor + 4 walls + ramp)
Floor at y=-1, Player spawn at (0, 1.5, 8), FpsCamera at head height (y=1.7)
DirectionalLight + WorldEnvironment + UI label overlay (speed/state/chain)
- debug/debug_test_env.sh — launch wrapper for manual playtesting
No code changes: raw physics testbed. Intended to be opened as first scene in Godot window.
Closes#2 (test-level scene task)