[Agentic DX] cihai-cli: low-to-high lift output-contract roadmap

[tony]

Context

Review focused on src/cihai_cli/cli.py, formatter/output behavior, and command parity.

Goal

Provide consistent machine-output and predictable command contracts for automation.

Low-lift ideas

• Add --format table|yaml|json|ndjson (or equivalent --json/--ndjson) to data-returning commands.
• Route primary command payloads to stdout directly (not logging) to avoid parsing noise.
• Document exit code semantics for not-found/error/success.

Medium-lift ideas

• Add shared output layer aligned with unihan-etl output utilities.
• Add explicit bootstrap behavior flags (--bootstrap, --no-bootstrap) for deterministic automation.
• Add contract tests for machine-output modes.

High-lift ideas

• Support streaming NDJSON for multi-result reverse lookups.
• Publish output schema/version for automation clients.

Done when

• CLI output is stable for pipes and tools.
• Command side effects are explicit.
• Schema evolution is manageable for downstream consumers.