Add tag, gitea-release, and release targets to encode the corrected
versioning process (no v-prefix). VERSION is now overridable via the
command line for use in make release VERSION=x.y.z.
- Add mobile/tablet responsive breakpoints to web UI
- Redesign cards as full-bleed poster layout with gradient overlay
- Add skeleton loading state, comic count badge, and search icon
- Switch to Docker image format for registry compatibility
- Add docker-build and docker-push Makefile targets with versioned tags
- Update README to document web UI, Docker deployment, and serve command
