fix(ci): fetch GeoLite2 mmdb before agent build

Agent embeds GeoLite2-Country.mmdb but the file is not checked into the
repository. Download it in CI, Docker, and Makefile build paths via
scripts/fetch-agent-geoip-mmdb.sh, and correct the gitignore exception
path for the geoipdata package.

scripts/fetch-agent-geoip-mmdb.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+TARGET="${ROOT}/internal/apps/agent/geoipdata/GeoLite2-Country.mmdb"
+URL="${GEOIP_MMDB_URL:-https://raw.githubusercontent.com/Loyalsoldier/geoip/release/GeoLite2-Country.mmdb}"
+
+mkdir -p "$(dirname "$TARGET")"
+curl -fsSL -o "$TARGET" "$URL"
+
+if [ ! -s "$TARGET" ]; then
+  echo "downloaded GeoIP database is empty: $TARGET" >&2
+  exit 1
+fi
+
+echo "GeoIP database ready: $TARGET"