fix(db): expand child_jobs model_type constraint to all 10 models

The original migration 046 only allowed DQN, PPO, MAMBA-2, TFT, TLOB.
Now includes TGGN, LIQUID, KAN, XLSTM, DIFFUSION.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

migrations/049_expand_child_jobs_model_types.sql

@@ -0,0 +1,7 @@
+-- Migration 049: Expand child_jobs model_type constraint to all 10 supported models
+-- The original constraint (migration 046) only allowed DQN, PPO, MAMBA-2, TFT, TLOB.
+-- We now support 10 model types via UnifiedTrainable adapters.
+ALTER TABLE child_jobs DROP CONSTRAINT IF EXISTS chk_child_job_model_type;
+ALTER TABLE child_jobs ADD CONSTRAINT chk_child_job_model_type CHECK (
+    model_type IN ('DQN', 'PPO', 'MAMBA-2', 'TFT', 'TLOB', 'TGGN', 'LIQUID', 'KAN', 'XLSTM', 'DIFFUSION')
+);