Route the bull's hits through the typed DamageEvent pipeline

Hitbox now builds a DamageEvent (cause + hit position + shaped knock-up) and
calls the bull's new receive_damage(), instead of two stringly Object.call()s.
receive_damage adapts over the existing pip/knock-up logic so behaviour is
identical -- the characterization test drives both the string and typed paths
and asserts the same outcomes. Wire fx/damage/harness tests into run_tests.sh
+ CLAUDE.md. All hitbox guard tests green (stab, bear hitbox, ram, charge).

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

run_tests.sh

@@ -18,6 +18,14 @@ echo ""
 echo "=== Logic tests ==="
 "$GODOT" --headless --script tests/logic_test.gd
 
+echo ""
+echo "=== Damage pipeline (bull's hit reception through DamageEvent) ==="
+"$GODOT" --headless --script tests/damage_pipeline_test.gd
+
+echo ""
+echo "=== FX gallery smoke (every registered Fx effect spawns + frees) ==="
+"$GODOT" --headless --script tests/fx_gallery_test.gd
+
 echo ""
 echo "=== Console focus tests ==="
 "$GODOT" --headless --script tests/console_focus_test.gd