feat(l1): category service (defaults + hard floor) and AI action keys

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/app/core/config.py

@@ -211,6 +211,10 @@ class Settings(BaseSettings):
         # concrete rendered script so a draft_template can be proposed.
         # Creates a persistent library artifact on accept, so Sonnet.
         "template_extraction": "standard",
+        # L1 AI tree builder (Phase 2A): per-node generation is latency-sensitive
+        # on a live call → Sonnet; classification is a short label task → Haiku.
+        "l1_realtime_build": "standard",
+        "l1_classify": "fast",
     }
 
     def get_model_for_action(self, action_type: str) -> str: