diff --git a/backend/app/db.py b/backend/app/db.py
index eea3c34..c696db5 100755
--- a/backend/app/db.py
+++ b/backend/app/db.py
@@ -281,6 +281,66 @@ CREATE TABLE IF NOT EXISTS integration_vouchers (
     created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
 );
 
+CREATE TABLE IF NOT EXISTS history_revisions (
+    id BIGSERIAL PRIMARY KEY,
+    scope TEXT NOT NULL DEFAULT 'organization',
+    revision_label TEXT NOT NULL,
+    created_by_user_id BIGINT,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    note TEXT NOT NULL DEFAULT ''
+);
+
+CREATE TABLE IF NOT EXISTS member_versions (
+    id BIGSERIAL PRIMARY KEY,
+    member_id INTEGER NOT NULL REFERENCES members(id) ON DELETE CASCADE,
+    name TEXT NOT NULL,
+    company TEXT NOT NULL DEFAULT '',
+    rank TEXT NOT NULL DEFAULT '',
+    role TEXT NOT NULL DEFAULT '',
+    department TEXT NOT NULL DEFAULT '',
+    grp TEXT NOT NULL DEFAULT '',
+    division TEXT NOT NULL DEFAULT '',
+    team TEXT NOT NULL DEFAULT '',
+    cell TEXT NOT NULL DEFAULT '',
+    work_status TEXT NOT NULL DEFAULT '',
+    work_time TEXT NOT NULL DEFAULT '',
+    phone TEXT NOT NULL DEFAULT '',
+    email TEXT NOT NULL DEFAULT '',
+    photo_url TEXT NOT NULL DEFAULT '',
+    valid_from TIMESTAMPTZ NOT NULL,
+    valid_to TIMESTAMPTZ,
+    revision_no BIGINT NOT NULL,
+    changed_by_user_id BIGINT,
+    change_reason TEXT NOT NULL DEFAULT '',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS seat_assignment_versions (
+    id BIGSERIAL PRIMARY KEY,
+    member_id INTEGER NOT NULL REFERENCES members(id) ON DELETE CASCADE,
+    seat_map_id INTEGER REFERENCES seat_maps(id) ON DELETE CASCADE,
+    seat_slot_id INTEGER REFERENCES seat_slots(id) ON DELETE CASCADE,
+    seat_label TEXT NOT NULL DEFAULT '',
+    valid_from TIMESTAMPTZ NOT NULL,
+    valid_to TIMESTAMPTZ,
+    revision_no BIGINT NOT NULL,
+    changed_by_user_id BIGINT,
+    change_reason TEXT NOT NULL DEFAULT '',
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+CREATE TABLE IF NOT EXISTS entity_change_events (
+    id BIGSERIAL PRIMARY KEY,
+    entity_type TEXT NOT NULL,
+    entity_id BIGINT NOT NULL,
+    action_type TEXT NOT NULL,
+    revision_no BIGINT NOT NULL,
+    changed_by_user_id BIGINT,
+    changed_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    change_reason TEXT NOT NULL DEFAULT '',
+    patch_json JSONB NOT NULL DEFAULT '{}'::jsonb
+);
+
 CREATE SCHEMA IF NOT EXISTS auth;
 
 CREATE TABLE IF NOT EXISTS auth.users (
@@ -474,6 +534,18 @@ ON integration_vouchers (project_code, project_name);
 CREATE UNIQUE INDEX IF NOT EXISTS integration_project_category_mappings_key_idx
 ON integration_project_category_mappings (source_key, normalized_project_key);
 
+CREATE INDEX IF NOT EXISTS member_versions_member_time_idx
+ON member_versions (member_id, valid_from, valid_to);
+
+CREATE INDEX IF NOT EXISTS seat_assignment_versions_member_time_idx
+ON seat_assignment_versions (member_id, valid_from, valid_to);
+
+CREATE INDEX IF NOT EXISTS history_revisions_scope_created_idx
+ON history_revisions (scope, created_at DESC);
+
+CREATE INDEX IF NOT EXISTS entity_change_events_entity_idx
+ON entity_change_events (entity_type, entity_id, changed_at DESC);
+
 DO $$
 BEGIN
     IF NOT EXISTS (
@@ -556,6 +628,7 @@ def init_db(max_retries: int = 20, retry_delay: float = 2.0) -> None:
                 with conn.cursor() as cur:
                     cur.execute(SCHEMA_SQL)
                     cur.execute(MIGRATION_SQL)
+                    ensure_history_backfill(cur)
                 conn.commit()
             return
         except psycopg.OperationalError as exc:
@@ -563,3 +636,69 @@ def init_db(max_retries: int = 20, retry_delay: float = 2.0) -> None:
             time.sleep(retry_delay)
     if last_error is not None:
         raise last_error
+
+
+def ensure_history_backfill(cur) -> None:
+    cur.execute(
+        """
+        SELECT id
+        FROM history_revisions
+        WHERE scope = 'organization'
+          AND revision_label = 'initial-backfill'
+        ORDER BY id ASC
+        LIMIT 1
+        """
+    )
+    row = cur.fetchone()
+    if row is None:
+        cur.execute(
+            """
+            INSERT INTO history_revisions (scope, revision_label, note)
+            VALUES ('organization', 'initial-backfill', 'Seeded from current members and seat_positions state')
+            RETURNING id
+            """
+        )
+        revision_id = int(cur.fetchone()["id"])
+    else:
+        revision_id = int(row["id"])
+
+    cur.execute(
+        """
+        INSERT INTO member_versions (
+            member_id, name, company, rank, role, department, grp, division, team, cell,
+            work_status, work_time, phone, email, photo_url,
+            valid_from, valid_to, revision_no, changed_by_user_id, change_reason
+        )
+        SELECT
+            m.id, m.name, COALESCE(m.company, ''), COALESCE(m.rank, ''), COALESCE(m.role, ''),
+            COALESCE(m.department, ''), COALESCE(m.grp, ''), COALESCE(m.division, ''), COALESCE(m.team, ''), COALESCE(m.cell, ''),
+            COALESCE(m.work_status, ''), COALESCE(m.work_time, ''), COALESCE(m.phone, ''), COALESCE(m.email, ''), COALESCE(m.photo_url, ''),
+            COALESCE(m.updated_at, m.created_at, NOW()), NULL, %s, NULL, 'initial-backfill'
+        FROM members AS m
+        WHERE NOT EXISTS (
+            SELECT 1
+            FROM member_versions mv
+            WHERE mv.member_id = m.id
+        )
+        """,
+        (revision_id,),
+    )
+
+    cur.execute(
+        """
+        INSERT INTO seat_assignment_versions (
+            member_id, seat_map_id, seat_slot_id, seat_label,
+            valid_from, valid_to, revision_no, changed_by_user_id, change_reason
+        )
+        SELECT
+            sp.member_id, sp.seat_map_id, sp.seat_slot_id, COALESCE(sp.seat_label, ''),
+            COALESCE(sp.updated_at, NOW()), NULL, %s, NULL, 'initial-backfill'
+        FROM seat_positions AS sp
+        WHERE NOT EXISTS (
+            SELECT 1
+            FROM seat_assignment_versions sav
+            WHERE sav.member_id = sp.member_id
+        )
+        """,
+        (revision_id,),
+    )
diff --git a/docker-compose.8081.yml b/docker-compose.8081.yml
new file mode 100644
index 0000000..033a050
--- /dev/null
+++ b/docker-compose.8081.yml
@@ -0,0 +1,78 @@
+services:
+  proxy:
+    image: nginx:1.27-alpine
+    depends_on:
+      frontend:
+        condition: service_healthy
+      backend:
+        condition: service_healthy
+    ports:
+      - "8081:80"
+    volumes:
+      - ./proxy/nginx.conf:/etc/nginx/conf.d/default.conf:ro
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD-SHELL", "wget -q --spider http://127.0.0.1/ || exit 1"]
+      interval: 15s
+      timeout: 5s
+      retries: 5
+      start_period: 10s
+
+  frontend:
+    build:
+      context: .
+      dockerfile: frontend/Dockerfile
+    volumes:
+      - ./frontend/public:/usr/share/nginx/html:ro
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD-SHELL", "wget -q --spider http://127.0.0.1/ || exit 1"]
+      interval: 15s
+      timeout: 5s
+      retries: 5
+      start_period: 10s
+
+  backend:
+    build:
+      context: .
+      dockerfile: backend/Dockerfile
+    command: uvicorn backend.app.main:app --host 0.0.0.0 --port 8000 --reload
+    env_file:
+      - .env
+    depends_on:
+      db:
+        condition: service_healthy
+    volumes:
+      - ./backend/app:/app/backend/app:ro
+      - ./DashBoard-organization.html:/app/legacy/DashBoard-organization.html:ro
+      - ./DashBoard-organization-backup.html:/app/legacy/DashBoard-organization-backup.html:ro
+      - ./legacy/static:/app/legacy/static:ro
+      - ./incoming-files:/app/incoming-files:ro
+      - uploads_data:/data/uploads
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD-SHELL", "python -c \"import urllib.request; urllib.request.urlopen('http://127.0.0.1:8000/api/health')\" || exit 1"]
+      interval: 15s
+      timeout: 5s
+      retries: 8
+      start_period: 20s
+
+  db:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_DB: ${POSTGRES_DB}
+      POSTGRES_USER: ${POSTGRES_USER}
+      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U ${POSTGRES_USER} -d ${POSTGRES_DB}"]
+      interval: 10s
+      timeout: 5s
+      retries: 10
+      start_period: 10s
+
+volumes:
+  postgres_data:
+  uploads_data:
diff --git a/docs/DEVELOPMENT_HISTORY.md b/docs/DEVELOPMENT_HISTORY.md
index d916c9f..e33fc51 100644
--- a/docs/DEVELOPMENT_HISTORY.md
+++ b/docs/DEVELOPMENT_HISTORY.md
@@ -214,6 +214,16 @@
 - 특정 날짜의 자리배치도 재구성 가능
 - 기간 비교나 변경 추적 UI로 확장 가능
 
+### 현재 반영 상태
+
+- `history_revisions`
+- `member_versions`
+- `seat_assignment_versions`
+- `entity_change_events`
+
+초기 단계로 테이블과 baseline backfill 경로를 먼저 추가했다.
+아직 조직도/자리배치도 쓰기 API가 매 수정마다 version row 를 append 하도록 완전히 전환된 상태는 아니다.
+
 ### 설계 문서
 
 - [HISTORY_ASOF_DB_PLAN.md](/home/hyunho/projects/mh-dashboard-organization/docs/HISTORY_ASOF_DB_PLAN.md)
diff --git a/docs/DEV_PROD_DB_PROTOCOL.md b/docs/DEV_PROD_DB_PROTOCOL.md
index 0397805..5e84cc4 100644
--- a/docs/DEV_PROD_DB_PROTOCOL.md
+++ b/docs/DEV_PROD_DB_PROTOCOL.md
@@ -11,14 +11,20 @@
 ### 코드 경로
 
 - 공개용 `8080`: `/home/hyunho/projects/mh-dashboard-organization`
-- 작업용 `8081`: `/tmp/mh-dashboard-organization-dev`
+- 작업용 `8081`: `/home/hyunho/projects/mh-dashboard-organization`
+
+### 작업용 Compose 기준
+
+- 공개용 `8080` stack: `docker-compose.yml`
+- 작업용 `8081` stack: `docker-compose.8081.yml`
+- 작업용 project name 기본값: `mh-dashboard-organization-dev`
 
 ### DB 볼륨
 
 - 공개용 `8080`: `mh-dashboard-organization_postgres_data`
 - 작업용 `8081`: `mh-dashboard-organization-dev_postgres_data`
 
-즉 현재는 코드도 분리, DB도 분리 상태다.
+즉 현재는 코드 workspace는 같아도 compose project 와 DB volume 이 분리된 상태다.
 
 ## 정본 기준
 
@@ -161,11 +167,12 @@
 반복 가능한 동기화 스크립트:
 
 - [sync_prod_db_to_dev.sh](/home/hyunho/projects/mh-dashboard-organization/scripts/sync_prod_db_to_dev.sh)
+- [docker-compose.8081.yml](/home/hyunho/projects/mh-dashboard-organization/docker-compose.8081.yml)
 
 사용 방법:
 
 ```bash
-chmod +x scripts/sync_prod_db_to_dev.sh
+docker compose -p mh-dashboard-organization-dev --env-file .env -f docker-compose.8081.yml up -d
 ./scripts/sync_prod_db_to_dev.sh minimal
 ./scripts/sync_prod_db_to_dev.sh full
 ```
@@ -179,6 +186,11 @@ chmod +x scripts/sync_prod_db_to_dev.sh
 
 주의:
 
+- 스크립트는 동기화 전에 `8081`의 `proxy`, `frontend`, `backend` 를 잠시 멈춘다
+- 이유는 중간 상태를 읽는 API 요청과 DB truncate/restore 가 충돌하면 deadlock 또는 부분 검증이 발생할 수 있기 때문이다
 - 스크립트는 `8080` DB 데이터를 덤프해서 `8081` DB의 대상 테이블을 비우고 다시 적재한다
 - `8081`에서만 존재하던 대상 테이블 데이터는 사라진다
+- `seat_positions` 는 portable CSV 경로로 별도 복원한다
+- 복원 후 `members.seat_label`, `auth.users`, history backfill 을 다시 맞춘다
+- 실행 후 주요 테이블 수량과 seat 정합성 수치를 출력한다
 - 따라서 실행 전 현재 작업용 DB 상태를 유지해야 하면 별도 백업 후 실행한다
diff --git a/docs/REGRESSION_CHECKLIST.md b/docs/REGRESSION_CHECKLIST.md
index 71c4292..7d431f9 100644
--- a/docs/REGRESSION_CHECKLIST.md
+++ b/docs/REGRESSION_CHECKLIST.md
@@ -25,6 +25,7 @@
 - `8081` 작업용 접속 확인
 - `8080` 공개용 접속 확인
 - `docker compose ps`에서 `backend`, `frontend`, `proxy`, `db`가 정상인지 확인
+- `8081`은 기본적으로 `docker compose -p mh-dashboard-organization-dev --env-file .env -f docker-compose.8081.yml up -d` 로 기동
 
 ### 2. 데이터 동기화 범위 결정
 
diff --git a/scripts/sync_prod_db_to_dev.sh b/scripts/sync_prod_db_to_dev.sh
index 792c813..cfa4d18 100755
--- a/scripts/sync_prod_db_to_dev.sh
+++ b/scripts/sync_prod_db_to_dev.sh
@@ -4,7 +4,9 @@ set -euo pipefail
 
 ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 PROD_DIR="${ROOT_DIR}"
-DEV_DIR="${DEV_DIR:-/tmp/mh-dashboard-organization-dev}"
+DEV_DIR="${DEV_DIR:-${ROOT_DIR}}"
+DEV_PROJECT_NAME="${DEV_PROJECT_NAME:-mh-dashboard-organization-dev}"
+DEV_COMPOSE_FILE="${DEV_COMPOSE_FILE:-${ROOT_DIR}/docker-compose.8081.yml}"
 SCOPE="${1:-minimal}"
 
 if [[ ! -f "${PROD_DIR}/docker-compose.yml" ]]; then
@@ -14,7 +16,13 @@ fi
 
 if [[ ! -f "${DEV_DIR}/docker-compose.yml" ]]; then
   echo "Development workspace not found: ${DEV_DIR}" >&2
-  echo "Set DEV_DIR=/path/to/dev-copy if the dev workspace moved." >&2
+  echo "Set DEV_DIR=/path/to/workspace if the dev workspace moved." >&2
+  exit 1
+fi
+
+if [[ ! -f "${DEV_COMPOSE_FILE}" ]]; then
+  echo "Development compose file not found: ${DEV_COMPOSE_FILE}" >&2
+  echo "Set DEV_COMPOSE_FILE=/path/to/dev-compose.yml if the dev compose file moved." >&2
   exit 1
 fi
 
@@ -74,21 +82,30 @@ case "${SCOPE}" in
 esac
 
 PROD_COMPOSE=(docker compose --project-directory "${PROD_DIR}")
-DEV_COMPOSE=(docker compose --project-directory "${DEV_DIR}")
+DEV_COMPOSE=(docker compose -p "${DEV_PROJECT_NAME}" --env-file "${DEV_DIR}/.env" -f "${DEV_COMPOSE_FILE}")
+
+run_compose() {
+  local dir="$1"
+  shift
+  (cd "${dir}" && "$@")
+}
 
 require_service() {
   local dir="$1"
   shift
-  (cd "${dir}" && "$@") >/dev/null
+  run_compose "${dir}" "$@" >/dev/null
 }
 
-echo "[1/6] Checking source and target stacks"
+echo "[1/8] Checking source and target stacks"
 require_service "${PROD_DIR}" "${PROD_COMPOSE[@]}" ps
 require_service "${DEV_DIR}" "${DEV_COMPOSE[@]}" ps
 
-echo "[2/6] Ensuring db containers are reachable"
-(cd "${PROD_DIR}" && "${PROD_COMPOSE[@]}" exec -T db pg_isready -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}") >/dev/null
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T db pg_isready -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}") >/dev/null
+echo "[2/8] Ensuring db containers are reachable"
+run_compose "${PROD_DIR}" "${PROD_COMPOSE[@]}" exec -T db pg_isready -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db pg_isready -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null
+
+echo "[3/8] Pausing 8081 app services to avoid partial reads during sync"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" stop proxy frontend backend >/dev/null
 
 WORK_DIR="$(mktemp -d)"
 cleanup() {
@@ -100,53 +117,54 @@ DUMP_FILE="${WORK_DIR}/prod_to_dev_${SCOPE}.sql"
 TRUNCATE_FILE="${WORK_DIR}/truncate_${SCOPE}.sql"
 SEAT_POSITIONS_FILE="${WORK_DIR}/seat_positions.csv"
 SEQUENCE_FIX_FILE="${WORK_DIR}/sequence_fix.sql"
-AUTH_SYNC_FILE="${WORK_DIR}/auth_sync.py"
 
-echo "[3/6] Building truncate script for ${SCOPE} scope"
+echo "[4/8] Building truncate script for ${SCOPE} scope"
 {
   echo "BEGIN;"
   echo "SET session_replication_role = replica;"
-  printf 'TRUNCATE TABLE %s RESTART IDENTITY CASCADE;\n' "$(IFS=,; echo "${TABLES[*]}")"
+  printf 'TRUNCATE TABLE %s RESTART IDENTITY CASCADE;\n' "$(printf 'public.%s,' "${TABLES[@]}" | sed 's/,$//')"
   echo "SET session_replication_role = DEFAULT;"
   echo "COMMIT;"
 } > "${TRUNCATE_FILE}"
 
-echo "[4/6] Dumping ${SCOPE} data from 8080 source DB"
+echo "[5/8] Dumping ${SCOPE} data from 8080 source DB"
 TABLE_ARGS=()
 for table in "${TABLES[@]}"; do
   TABLE_ARGS+=(-t "public.${table}")
 done
-(cd "${PROD_DIR}" && "${PROD_COMPOSE[@]}" exec -T db \
+run_compose "${PROD_DIR}" "${PROD_COMPOSE[@]}" exec -T db \
   pg_dump -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" \
   --data-only --column-inserts --disable-triggers --no-owner --no-privileges \
-  "${TABLE_ARGS[@]}") > "${DUMP_FILE}"
+  "${TABLE_ARGS[@]}" > "${DUMP_FILE}"
 
-echo "[4.5/6] Exporting seat_positions in portable format"
-(cd "${PROD_DIR}" && "${PROD_COMPOSE[@]}" exec -T db \
+echo "[5.5/8] Exporting seat_positions in portable format"
+run_compose "${PROD_DIR}" "${PROD_COMPOSE[@]}" exec -T db \
   psql -At -F ',' -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" \
   -c "COPY (
         SELECT member_id, seat_map_id, seat_slot_id, row_index, col_index, seat_label, updated_at
         FROM public.seat_positions
         ORDER BY member_id
-      ) TO STDOUT WITH CSV") > "${SEAT_POSITIONS_FILE}"
+      ) TO STDOUT WITH CSV" > "${SEAT_POSITIONS_FILE}"
 
-echo "[5/6] Truncating target tables in 8081 dev DB"
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T db \
-  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null) < "${TRUNCATE_FILE}"
+echo "[6/8] Truncating target tables in 8081 dev DB"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db \
+  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null < "${TRUNCATE_FILE}"
 
-echo "[6/6] Restoring dumped data into 8081 dev DB"
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T db \
-  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null) < "${DUMP_FILE}"
+echo "[7/8] Restoring dumped data into 8081 dev DB"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db \
+  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null < "${DUMP_FILE}"
 
-echo "[6.5/6] Restoring portable seat_positions and rebuilding auth users"
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T db \
+echo "[7.5/8] Restoring portable seat_positions and rebuilding auth users"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db \
   psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" \
-  -c "DELETE FROM public.seat_positions" >/dev/null)
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T db \
+  -c "DELETE FROM public.seat_positions" >/dev/null
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db \
   psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" \
-  -c "COPY public.seat_positions (member_id, seat_map_id, seat_slot_id, row_index, col_index, seat_label, updated_at) FROM STDIN WITH CSV" >/dev/null) < "${SEAT_POSITIONS_FILE}"
-cat > "${AUTH_SYNC_FILE}" <<'PY'
+  -c "COPY public.seat_positions (member_id, seat_map_id, seat_slot_id, row_index, col_index, seat_label, updated_at) FROM STDIN WITH CSV" >/dev/null < "${SEAT_POSITIONS_FILE}"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" up -d backend >/dev/null
+AUTH_SYNC_PY="$(cat <<'PY'
 from backend.app.main import get_conn, sync_auth_users_from_members
+from backend.app.db import ensure_history_backfill
 
 with get_conn() as conn:
     with conn.cursor() as cur:
@@ -160,12 +178,14 @@ with get_conn() as conn:
             """
         )
         sync_auth_users_from_members(cur)
+        ensure_history_backfill(cur)
     conn.commit()
-print("members, seat labels, and auth users synced")
+print("members, seat labels, auth users, and history backfill synced")
 PY
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T backend python -) < "${AUTH_SYNC_FILE}"
+)"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T backend python -c "${AUTH_SYNC_PY}"
 
-echo "[6.8/6] Resetting serial sequences"
+echo "[7.8/8] Resetting serial sequences"
 {
   echo "SELECT setval(pg_get_serial_sequence('public.members', 'id'), COALESCE((SELECT MAX(id) FROM public.members), 1), true);"
   echo "SELECT setval(pg_get_serial_sequence('public.member_aliases', 'id'), COALESCE((SELECT MAX(id) FROM public.member_aliases), 1), true);"
@@ -188,11 +208,53 @@ echo "[6.8/6] Resetting serial sequences"
     echo "SELECT setval(pg_get_serial_sequence('public.integration_vouchers', 'id'), COALESCE((SELECT MAX(id) FROM public.integration_vouchers), 1), true);"
   fi
 } > "${SEQUENCE_FIX_FILE}"
-(cd "${DEV_DIR}" && "${DEV_COMPOSE[@]}" exec -T db \
-  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null) < "${SEQUENCE_FIX_FILE}"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db \
+  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" >/dev/null < "${SEQUENCE_FIX_FILE}"
+
+VERIFY_SQL="${WORK_DIR}/verify_${SCOPE}.sql"
+{
+  cat <<'SQL'
+SELECT 'members' AS table_name, COUNT(*)::text AS value FROM public.members
+UNION ALL
+SELECT 'member_retirements', COUNT(*)::text FROM public.member_retirements
+UNION ALL
+SELECT 'seat_maps', COUNT(*)::text FROM public.seat_maps
+UNION ALL
+SELECT 'seat_slots', COUNT(*)::text FROM public.seat_slots
+UNION ALL
+SELECT 'seat_positions', COUNT(*)::text FROM public.seat_positions
+UNION ALL
+SELECT 'members_with_seat_label', COUNT(*)::text FROM public.members WHERE COALESCE(seat_label, '') <> ''
+UNION ALL
+SELECT 'seat_positions_without_slot', COUNT(*)::text FROM public.seat_positions WHERE seat_slot_id IS NULL
+UNION ALL
+SELECT 'seat_label_mismatch', COUNT(*)::text
+FROM public.members m
+JOIN public.seat_positions sp ON sp.member_id = m.id
+WHERE COALESCE(m.seat_label, '') <> COALESCE(sp.seat_label, '')
+UNION ALL
+SELECT 'auth_users', COUNT(*)::text FROM auth.users
+ORDER BY table_name;
+SQL
+  if [[ "${SCOPE}" == "analysis" || "${SCOPE}" == "full" ]]; then
+    cat <<'SQL'
+SELECT 'integration_work_logs', COUNT(*)::text FROM public.integration_work_logs
+UNION ALL
+SELECT 'integration_vouchers', COUNT(*)::text FROM public.integration_vouchers
+ORDER BY 1;
+SQL
+  fi
+} > "${VERIFY_SQL}"
+
+echo "[8/8] Restarting 8081 app services and printing verification snapshot"
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" up -d frontend proxy >/dev/null
+run_compose "${DEV_DIR}" "${DEV_COMPOSE[@]}" exec -T db \
+  psql -q -v ON_ERROR_STOP=1 -U "${POSTGRES_USER:-orgapp}" -d "${POSTGRES_DB:-orgdb}" -f - < "${VERIFY_SQL}"
 
 echo
 echo "Sync complete."
 echo "Source: ${PROD_DIR} (8080)"
 echo "Target: ${DEV_DIR} (8081)"
+echo "Dev compose: ${DEV_COMPOSE_FILE}"
+echo "Dev project: ${DEV_PROJECT_NAME}"
 echo "Scope : ${SCOPE}"