fix(ops): pg-backup momo_analytics 改用 docker exec (無對外 port)

momo-db 容器無 port binding，TCP 127.0.0.1:5432 連到 host PG 非容器。
改用 docker exec momo-db pg_dump，實際備份 91M。

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

scripts/ops/pg-backup.sh

@@ -75,14 +75,18 @@ main() {
     # awoooi_prod (host PostgreSQL, TCP)
     results+=("$(backup_db "awoooi_prod" "127.0.0.1" "awoooi" "awoooi_prod_2026" "awoooi_prod")")
 
-    # momo_analytics (momo-db 容器，透過 host TCP)
-    local momo_pass
-    momo_pass=$(docker inspect momo-db --format '{{range .Config.Env}}{{println .}}{{end}}' 2>/dev/null | grep POSTGRES_PASSWORD | cut -d= -f2)
-    if [[ -n "$momo_pass" ]]; then
-        results+=("$(backup_db "momo_analytics" "127.0.0.1" "momo" "$momo_pass" "momo_analytics")")
+    # momo_analytics (momo-db 容器，無對外 port，用 docker exec 直接 dump)
+    local outfile_momo="${BACKUP_DIR}/momo_analytics_${TIMESTAMP}.sql.gz"
+    log "開始備份 momo_analytics (docker exec) → ${outfile_momo}"
+    if docker exec momo-db pg_dump -U momo momo_analytics 2>/dev/null | gzip > "$outfile_momo"; then
+        local size_momo
+        size_momo=$(du -sh "$outfile_momo" | cut -f1)
+        log "✅ momo_analytics 備份完成 (${size_momo})"
+        results+=("success:momo_analytics:${size_momo}")
     else
-        log "⚠️ momo-db 密碼未取得，跳過 momo_analytics"
-        results+=("skipped:momo_analytics")
+        log "❌ momo_analytics 備份失敗"
+        rm -f "$outfile_momo"
+        results+=("failed:momo_analytics")
     fi
 
     # 清理舊備份