Switch default output format from `text` to `json` (12.14)

[josecelano]

Overview

Switch the default CLI output format from text to json (roadmap task 12.14).

This is the final task in epic #348. All previous commands (12.1–12.13) now have JSON output implemented, satisfying the prerequisite that prevented this change.

Specification

See: docs/issues/switch-default-output-format-to-json.md

Changes Required

• Move #[default] from OutputFormat::Text to OutputFormat::Json in src/presentation/cli/input/cli/output_format.rs
• Update default_value = "text" → default_value = "json" and doc comment in src/presentation/cli/input/cli/args.rs
• Update doctest asserting OutputFormat::default() is Text
• Update any other tests/examples relying on the old default

Breaking Change

Users relying on unformatted text output without --output-format will now receive JSON. Explicit --output-format text is required to restore the old behaviour.

Acceptance Criteria

• OutputFormat::default() returns OutputFormat::Json
• Running any command without --output-format produces valid JSON
• --output-format text still produces human-readable text
• All tests pass, all linters pass

Related

• Part of epic EPIC: Add JSON output format support #348 (Add JSON output format support)
• Prerequisite: Add JSON output to register command (12.13) #396 ✅ (final command with JSON output)