[Refactor] Phase 1: Create Network Domain Types (P1.1, P1.2)

[josecelano]

Overview

This task creates domain types for Docker Compose networks and migrates service configurations from Vec<String> to type-safe Vec<Network>. This is PR 4 in the 5-PR refactoring strategy.

Parent Epic: #287

Goals

• Create type-safe Network enum to eliminate string-based network references
• Migrate all service configs to use domain network types
• Establish foundation for Phase 2 (automatic network derivation)

Implementation

P1.1: Create Network Domain Type

Create Network enum in src/domain/deployment/topology/network.rs:

• Database - Tracker ↔ MySQL
• Metrics - Tracker ↔ Prometheus
• Visualization - Prometheus ↔ Grafana
• Proxy - Caddy ↔ backend services

P1.2: Migrate Service Configs

Update all service configs to use Vec<Network> instead of Vec<String>:

• TrackerServiceConfig
• MysqlServiceConfig
• PrometheusServiceConfig
• GrafanaServiceConfig
• CaddyServiceConfig

Specification Document

See docs/issues/phase-1-network-domain-types.md for:

• Detailed code examples
• Unit test requirements
• Implementation checklist

Acceptance Criteria

• Pre-commit checks pass: ./scripts/pre-commit.sh
• Network enum exists with all four variants
• All service configs use Vec<Network> instead of Vec<String>
• Generated docker-compose.yml is identical to before refactoring
• Unit tests cover all network assignment rules

Related

• Refactoring Plan
• Phase 0 completed: [Refactor] Phase 0: Convert volumes to bind mounts with domain type #292