Add collapsible left "Script State" drawer on the play screen

Exposes the scripting `state` object (every variable scripts read/write
via state.x, persisted per-adventure) in a collapsible left rail that
refreshes after each turn. New owner-scoped GET
/api/adventures/{id}/script-state endpoint; the drawer only fetches
while open and shows an empty-state hint until a script sets a variable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TEpWMjnfPqzZ13nPMoGhs5

backend/app/routers/adventures.py

@@ -141,6 +141,17 @@ def get_adventure(
     return get_adventure_or_404(adventure_id, db, user)
 
 
+@router.get("/{adventure_id}/script-state")
+def get_script_state(
+    adventure_id: int, db: Session = Depends(get_db), user: models.User = CurrentUser
+):
+    """The scripting `state` object — every variable scripts read/write via
+    `state.x`, persisted after each hook. Empty {} until a script sets one."""
+    adventure = get_adventure_or_404(adventure_id, db, user)
+    state = adventure.script_state if isinstance(adventure.script_state, dict) else {}
+    return {"state": state}
+
+
 @router.patch("/{adventure_id}", response_model=schemas.AdventureOut)
 def update_adventure(
     adventure_id: int,