fix(ci): add migration baseline to backward-compat workflow

- Handles DBs where _prisma_migrations is missing (prisma db push history)
- Marks all existing migrations as applied before migrate deploy

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

.gitea/workflows/backward-compat.yml

@@ -25,6 +25,18 @@ jobs:
         run: |
           cd /tmp/api-server-compat
           npm ci
+          # Baseline: if _prisma_migrations is empty/missing, mark all existing migrations as applied
+          HAS_MIGS=$(npx prisma db execute --stdin <<< "SELECT COUNT(*) as cnt FROM _prisma_migrations" 2>/dev/null | grep -o '[0-9]*' | head -1 || echo "0")
+          if [ "$HAS_MIGS" = "0" ] || [ -z "$HAS_MIGS" ]; then
+            echo "[compat] Baselining existing migrations..."
+            for m in prisma/migrations/*/; do
+              m_name=$(basename "$m")
+              if [ "$m_name" != "backfill_chat_scope.sql" ] && [ "$m_name" != "migration_lock.toml" ]; then
+                DATABASE_URL="${{ secrets.DATABASE_URL }}" npx prisma migrate resolve --applied "$m_name" 2>/dev/null || true
+              fi
+            done
+            echo "[compat] Baseline complete."
+          fi
           DATABASE_URL="${{ secrets.DATABASE_URL }}" npx prisma migrate deploy
         timeout-minutes: 5