docs: note combat_turns migration deployment (bf-1bvca)

P0 fix for acb-index-builder crash:
- Added ALTER TABLE matches ADD COLUMN combat_turns migration
- Pushed to declarative-config@845d59d
- ArgoCD will sync and restart schema-init Pod

notes/bf-1bvca.md

@@ -0,0 +1,21 @@
+# P0: combat_turns Column Migration (bf-1bvca)
+
+## Problem
+`acb-index-builder` crashed every 15-min cycle with error: `column m.combat_turns does not exist`
+
+## Solution
+Added migration to declarative-config `k8s/iad-acb/ai-code-battle/acb-schema-init.yml`:
+
+```sql
+ALTER TABLE matches ADD COLUMN IF NOT EXISTS combat_turns INTEGER NOT NULL DEFAULT 0;
+```
+
+Also bumped rollout annotation from `v6-playlists-tables` to `v7-combat-turns` to force schema-init Pod restart.
+
+## Commit
+jedarden/declarative-config@845d59d
+
+## Verification
+- ArgoCD will auto-sync the ConfigMap and Deployment changes
+- Schema-init Pod will restart and apply the migration
+- acb-index-builder should succeed on next cycle