ci(db): bump migrate-down to 4 + verify verification_decisions (DEV-618)

0005_verification_decisions landed in DEV-612 but validate.yml still
assumed four migrations: it ran migrate down 3 (leaving
verification_decisions in place) and never grep'd for it on the up-pass.
Bump the roll-back to 4 and add the table to both the up-verify and
down-absent lists so the DB job matches reality again.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.forgejo/workflows/validate.yml

@@ -237,20 +237,21 @@ jobs:
           grep -q ' agents ' /tmp/dt-after-up.txt
           grep -q ' agent_keys ' /tmp/dt-after-up.txt
           grep -q ' approval_sessions ' /tmp/dt-after-up.txt
+          grep -q ' verification_decisions ' /tmp/dt-after-up.txt
 
       # Roll back everything on top of per_diem_rates (0001) — currently
-      # 0004_approval_sessions, 0003_agent_keys, 0002_agents — and verify
-      # per_diem_rates remains while the agent-side tables are gone. Keep
-      # this count equal to the number of migrations above 0001; bump when
-      # a new migration is added.
+      # 0005_verification_decisions, 0004_approval_sessions, 0003_agent_keys,
+      # 0002_agents — and verify per_diem_rates remains while the agent-side
+      # tables are gone. Keep this count equal to the number of migrations
+      # above 0001; bump when a new migration is added.
       - name: migrate down (all above per_diem_rates) + verify
         working-directory: ${{ github.workspace }}
         run: |
           set -euo pipefail
-          migrate -path db/trust/migrations -database "${DB_URL}" down 3
+          migrate -path db/trust/migrations -database "${DB_URL}" down 4
           psql "${DB_URL}" -c '\dt' | tee /tmp/dt-after-down.txt
           grep -q ' per_diem_rates ' /tmp/dt-after-down.txt
-          for table in agents agent_keys approval_sessions; do
+          for table in agents agent_keys approval_sessions verification_decisions; do
             if grep -q " ${table} " /tmp/dt-after-down.txt; then
               echo "FAIL: ${table} still present after migrate down" >&2
               exit 1