Adds "[Demo] The Goblin Ambush (HP script)": a combat scene whose script
tells the AI the current HP and to tag damage/healing as [HP-N]/[HP+N];
the AI decides the amounts, the onOutput hook applies them to state.hp
(clamped 0..100), hides the tags, and flags death at 0. Showcases the
new left State drawer with live variables. Verified through the real
quickjs engine: a simulated attack drops HP, a potion heals (clamped),
a fatal blow sets state.dead.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TEpWMjnfPqzZ13nPMoGhs5
