Fix Docker image platform mismatch in install-dev.sh causing exec format error

On x86_64 Linux VMs (e.g., Proxmox), Docker images in halfstack may be pulled with wrong architecture, causing containers to fail with:

exec /usr/bin/docker-entrypoint.sh: exec format error

Affected images include redis, minio, and various exporter images (oliver006/redis_exporter, prometheuscommunity/postgres-exporter, etc.).

Root cause: When QEMU binfmt_misc handlers are registered (e.g., from prior docker buildx or qemu-user-static usage), Docker may pull images for the wrong platform. Even after removing binfmt handlers, previously cached images retain the wrong architecture.

Fix: Set DOCKER_DEFAULT_PLATFORM=linux/amd64 before docker compose pull in install-dev.sh (around line 980), ensuring all images are pulled for the correct platform regardless of binfmt state.

JIRA Issue: BA-5531

Start in install-dev.sh around line 980 and inspect the docker compose pull command. Ensure the development images target linux/amd64, then verify the pull on an x86_64 Linux VM, including redis, minio, and exporter images, completes without exec format errors.

Written by the indexing model from the issue text.