CLI-DFT-006: Suspect/review JSON output missing timestamp and loader

[danieleades]

Observation

SPC-005 JSON sample includes a top-level timestamp and the command should show a spinner for large (>500) repositories; req review emits summary+links without timestamp and has no spinner.

Evidence

• req/src/cli/review.rs output_json/output_ndjson omit timestamp.
• No spinner/ASCII fallback in the command for large graphs.

Impact

JSON is missing the prescribed field and large repos get no progress feedback, diverging from SPC-005.

Expected

Include the timestamp field in JSON outputs and show the specified spinner during load for large repositories (UTF-8 or ASCII fallback).

Related Requirements

• Parents: CLI-SPC-005
• Tags: P3

Tracked in: CLI-DFT-006