[Feature] Backlog CLI Contract Reliability

[djm81]

Feature

Backlog module commands should follow the same CLI error contract as core: missing subcommands and required parameters show relevant help plus explicit missing information.

Parent Epic

• specfact backlog policy and evidence inputs #145 Backlog module epic

Source Tracking

• Introduced for tester reports Backlog auth command group errors with "Missing command" when invoked directly specfact-cli#591 and Inconsistent backlog CLI UX: daily works from adapter defaults, delta status requires project-id and reports undocumented repo requirements specfact-cli#592.

Acceptance Criteria

• Bare backlog command groups without a default action show help and missing-subcommand guidance.
• Backlog commands resolve documented configuration defaults consistently.
• Delta status exposes or documents all required parameters using kebab-case CLI option names.