feat: add JSON output to validate command (12.10)

[josecelano]

Overview

Closes #390 — Part of EPIC #348 (roadmap task 12.10).

Adds JSON output format support to the validate command. When --output-format json is passed, the command outputs a machine-readable JSON object to stdout. The existing human-readable text output is fully preserved.

Changes

New files

• src/presentation/cli/views/commands/validate/mod.rs — module declaration
• src/presentation/cli/views/commands/validate/view_data/validate_details.rs — ValidateDetailsData DTO with from_result(&Path, &ValidationResult) constructor
• src/presentation/cli/views/commands/validate/views/json_view.rs — JsonView with unit tests
• src/presentation/cli/views/commands/validate/views/text_view.rs — TextView with unit tests

Modified files

• src/presentation/cli/controllers/validate/handler.rs — add output_format: OutputFormat param to execute(), refactor complete_workflow() to dispatch to TextView/JsonView
• src/presentation/cli/dispatch/router.rs — pass context.output_format() to controller
• src/presentation/cli/views/commands/mod.rs — register pub mod validate
• docs/user-guide/commands/validate.md — add JSON output section

JSON Output

cargo run -- validate --env-file envs/lxd-local-example.json --output-format json 2>/dev/null

{
  "environment_name": "lxd-local-example",
  "config_file": "envs/lxd-local-example.json",
  "provider": "lxd",
  "is_valid": true,
  "has_prometheus": true,
  "has_grafana": true,
  "has_https": false,
  "has_backup": false
}

Text Output (unchanged)

cargo run -- validate --env-file envs/lxd-local-example.json 2>&1

⏳ [1/3] Loading configuration file...
⏳   ✓ Configuration file loaded (took 0ms)
⏳ [2/3] Validating JSON schema...
⏳   ✓ Schema validation passed (took 0ms)
⏳ [3/3] Validating configuration fields...
⏳   ✓ Field validation passed (took 0ms)

✅ Configuration file 'envs/lxd-local-example.json' is valid

Environment Details:
• Name: lxd-local-example
• Provider: lxd
• Prometheus: Enabled
• Grafana: Enabled
• HTTPS: Disabled
• Backups: Disabled

Quality Checks

• cargo run --bin linter all passes (stable + nightly)
• cargo machete — no unused dependencies
• cargo test — 417 tests pass, 0 failures
• Text output manually verified identical to pre-change output
• JSON output manually verified matches spec

Related

• Closes Add JSON output to validate command (12.10) #390
• Parent epic: EPIC: Add JSON output format support #348
• Spec: docs/issues/390-add-json-output-to-validate-command.md

[josecelano]

ACK 659870e