Add headless UI-layout robustness test

Asserts computed Control geometry instead of pixels: HUD/menu stay on-screen,
text fits its box, tap targets >=44px, and the options scroll can reach its
overflow -- across five resolutions plus a +40% pseudo-locale pass. Wired into
run_tests.sh and the CLAUDE.md test list. 16/16 pass headless.

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

CLAUDE.md

@@ -113,6 +113,7 @@ godot --headless --script tests/ragdoll_perf_test.gd  # on-hit spike breakdown:
 godot --headless --script tests/gameplay_test.gd      # full scene, bone sanity, ~4 s
 godot --headless --script tests/level_switch_test.gd  # no arena geometry leaks into the bear level, ~2 s
 godot --headless --script tests/touch_controls_test.gd # joystick self-heals: relayout/focus-out/vanished-touch never strand a stuck stick, ~2 s
+godot --headless --script tests/ui_layout_test.gd     # UI layout invariants (no pixels): HUD/menu stay on-screen, text fits, tap targets ≥44px, scroll works — across resolutions + pseudo-locale, ~6 s
 godot --headless --script tests/rigid_skin_test.gd    # web mesh conversion keeps every material (no bald / recoloured matadors), ~2 s
 godot --headless --script tests/bear_boss_test.gd     # bear boss moveset: routines, leap landing, hyper-armour, ~10 s
 godot --headless --script tests/bear_fx_test.gd       # bear attack-FX: each Bear_FX clip pops its mesh + self-hides, ~2 s