[Refactor] Phase 0: Convert volumes to bind mounts with domain type

[josecelano]

Overview

This task converts all Docker named volumes to bind mounts and introduces domain types (BindMount, MountOption) to represent volume mounts in a type-safe manner. This is a foundational change that simplifies the architecture by eliminating top-level volume declarations and provides observability into all persistent data via the ./storage/ directory.

Parent Epic: #287

Related:

• Refactoring Plan: Phase 0
• ADR: Bind Mount Standardization
• Supersedes volume decisions in ADR: Grafana Integration Pattern

Goals

• Convert all named volumes to bind mounts under ./storage/{service}/
• Remove top-level volumes: section from docker-compose template
• Create domain types (BindMount, MountOption) for type-safe mount representation
• Create Ansible playbooks to set correct directory ownership for Grafana and MySQL
• Update ADR status for grafana-integration-pattern.md (partially superseded)

Scope

Named Volumes to Convert

Service	Current Named Volume	New Bind Mount	Host Path
Caddy	caddy_data:/data	./storage/caddy/data:/data	./storage/caddy/data
Caddy	caddy_config_vol:/config	./storage/caddy/config:/config	./storage/caddy/config
Grafana	grafana_data:/var/lib/grafana	./storage/grafana/data:/var/lib/grafana	./storage/grafana/data
MySQL	mysql_data:/var/lib/mysql	./storage/mysql/data:/var/lib/mysql	./storage/mysql/data

Directory Ownership Requirements

Service	Container User	Required Host Ownership
Grafana	472:472 (grafana)	472:472
MySQL	999:999 (mysql)	999:999

Domain Types

New types in src/domain/deployment/topology/volume.rs:

• MountOption enum (ReadOnly, SELinux)
• BindMount struct (host_path, container_path, option)

Implementation Plan

1. Template Changes: Update docker-compose template (4 volume conversions + remove top-level volumes:)
2. Ansible Playbooks: Create create-grafana-storage.yml and create-mysql-storage.yml
3. Domain Types: Create BindMount and MountOption in domain layer
4. Documentation: Update ADR status

Acceptance Criteria

• Pre-commit checks pass: ./scripts/pre-commit.sh
• No named volumes remain in docker-compose template
• Top-level volumes: section is removed
• Grafana/MySQL storage playbooks create directories with correct ownership
• Domain types have unit tests
• E2E tests pass
• grafana-integration-pattern.md status updated

Specification

Full specification: docs/issues/292-convert-volumes-to-bind-mounts-with-domain-type.md