feat: implement environment show command (#241)

[josecelano]

Description

Implements the show command to display environment information with state-aware details. This command provides a read-only view of stored environment data, making it fast and reliable for users to inspect their deployment state.

Issue: Closes #241

Changes

Phase 1-5: Core Implementation ✅

• Added CLI subcommand and command dispatch
• Implemented ShowCommandHandler with state-aware extraction
• Created DTOs for environment info display
• Added comprehensive error handling with actionable messages
• Implemented MVC pattern with EnvironmentInfoView
• Added output formatting with UserOutput (no direct println!/eprintln!)
• Full unit test coverage for all states and error scenarios
• E2E tests for command validation

Phase 6: Creation Timestamp ✅

• Added created_at field to RuntimeOutputs domain model
• create command now populates creation timestamp using Clock service
• show command displays when environment was created
• Backward compatible with #[serde(default)]

Phase 7: Service URLs in RuntimeOutputs ✅

• Added service_endpoints field to RuntimeOutputs with ServiceEndpoints struct
• Added url crate dependency for proper URL handling
• run command stores service URLs after successful startup
• show command displays stored URLs with fallback to computing from config
• Refactored ServiceEndpoints::from_tracker_config into focused helper methods

Features

• State-aware display: Shows different information based on environment state (Created, Provisioned, Configured, Released, Running)
• Fast execution: < 100ms typical (reads stored data, no network calls)
• Clear error messages: Actionable guidance for all error scenarios
• Human-friendly output: Formatted with colors, spacing, and next-step guidance
• Creation timestamp: Shows when each environment was created
• Service URLs: Displays all tracker service endpoints for Running state

Testing

• ✅ All pre-commit checks pass
• ✅ Unit tests for all handler logic, states, and error scenarios
• ✅ E2E tests validate command execution and error handling
• ✅ Manual testing verified for Created state and error cases
• ✅ Doc tests pass
• ✅ Test coverage comprehensive

Architecture

• DDD Layers: Application (handler, DTOs, errors) + Presentation (CLI, view)
• Patterns: Command Handler, MVC (stateless view), DTO
• Output: All output via UserOutput (no direct stdio usage)
• Errors: Explicit enum types with thiserror (not anyhow)
• Module organization: Follows project conventions (imports first, public items at top)

Documentation

• Issue spec updated with all phases marked complete
• Inline code documentation (doc comments)
• Command help text available in --help

Related

• Feature specification: docs/features/environment-status-command/
• Architecture docs: docs/codebase-architecture.md, docs/contributing/ddd-layer-placement.md
• Output handling: docs/contributing/output-handling.md
• Error handling: docs/contributing/error-handling.md

Example Usage

# Show Created environment
$ torrust-tracker-deployer show my-environment
Environment: my-environment
State: Created
Provider: LXD
Created: 2026-01-07 12:11:29 UTC

Run 'provision' to create infrastructure.

# Error handling
$ torrust-tracker-deployer show non-existent
❌ Show command failed: Environment 'non-existent' not found
Tip: Use 'list' command to see available environments

[josecelano]

ACK 9d71a0b