CLI-DFT-012: Create command lacks req add alias

[danieleades]

Observation

SYS-022 states the command was renamed from req add to req create with an alias maintained; the CLI only exposes req create.

Evidence

• req/src/cli.rs registers Create(create::Command) with no alias for add.
• No command module or alias wiring for add exists.

Impact

Scripts and workflows using req add per SYS-022 cannot run; the implementation diverges from the documented interface.

Expected

Provide a req add alias (or subcommand) that maps to req create while preserving behaviour and exit codes described in SYS-022.

Related Requirements

• Parents: CLI-SYS-022
• Tags: P2

Tracked in: CLI-DFT-012