chore(ci): add Docker BuildKit examples, .dockerignore, CI cache docs; tune vite config

aether_container_env/ci_buildx_example.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Example CI script to build and push an image with buildx using registry cache.
+# This script is provider-agnostic and intended to be run inside CI where
+# Docker and buildx are available and authenticated against the registry.
+
+REGISTRY=${REGISTRY:-ghcr.io/ORG/REPO}
+IMAGE_TAG=${IMAGE_TAG:-staging}
+CACHE_REF=${CACHE_REF:-${REGISTRY}:cache}
+
+echo "Building ${REGISTRY}:${IMAGE_TAG} using registry cache ${CACHE_REF}"
+
+docker buildx build \
+  --push \
+  --tag ${REGISTRY}:${IMAGE_TAG} \
+  --cache-from type=registry,ref=${CACHE_REF} \
+  --cache-to type=registry,ref=${CACHE_REF},mode=max \
+  .
+
+echo "Build complete. Image: ${REGISTRY}:${IMAGE_TAG}"
+
+# Optional: instruct devs how to run locally with a local cache
+cat <<'EOF'
+Local test with BuildKit and local cache:
+DOCKER_BUILDKIT=1 docker build \
+  --tag myapp:staging \
+  --cache-to=type=local,dest=/tmp/docker-cache \
+  --cache-from=type=local,src=/tmp/docker-cache .
+
+Prune local builder cache older than 72 hours:
+docker builder prune --filter "until=72h" --force
+EOF