chore(scripts): add compose, k3s, backup, and media helpers

Automate image load, Helm install, database backup, and sample video regeneration.

scripts/compose-dev.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+# Dev / laptop stack (Traefik + localhost TLS + published DB ports).
+set -euo pipefail
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+
+if [[ ! -f .env ]]; then
+  echo "Missing .env — copy .env.example and fill secrets." >&2
+  exit 1
+fi
+
+exec docker compose \
+  -f deploy/compose/compose.yaml \
+  -f deploy/compose/compose.dev.yaml \
+  --env-file .env \
+  "$@"