v0.1.2

feat(ci): separate Docker images for server/agent/CLI + glibc fix (#45)

* feat(ci): publish separate Docker images for server, agent, and CLI

- ghcr.io/dbward-dev/dbward-server
- ghcr.io/dbward-dev/dbward-agent
- ghcr.io/dbward-dev/dbward (CLI)

Dockerfile.release uses multi-stage targets. Release workflow
builds all 3 images in parallel via matrix.

* fix: update all image references to use separate server/agent images

- Helm: server.image / agent.image split in values.yaml + templates
- k8s manifests: dbward-server / dbward-agent images
- ECS templates: per-component defaults
- Docs: server.md, agent.md, upgrading.md, CHANGELOG

* fix: address Codex review — Helm values dedup, restore command, fix docs

* docs: add Helm values breaking change note to upgrading.md