fix(spells): backfill casting times for all imported spells

data/spells/stabilize.json

@@ -5,6 +5,7 @@
   "range": "close",
   "save": "will",
   "base_dc": 10,
+  "cast_time": "standard",
   "effects": [],
   "description": "A cantrip: you touch a living creature with -1 or fewer hit points (up to close range) and stabilize it automatically, so it stops losing hit points until it takes more damage. Will negates (harmless). No combat effect encoded: the engine's dying/stabilization track is not exposed to the spell-effect system."
 }