feat(cli): QoL bundle — shell completion, --quiet, examples, confirmations, aliases

[cdot65]

Summary

Five QoL features in one bundle per issue #274.

Changes

• airs completion bash|zsh|fish — static scripts generated from the command tree (subcommands, aliases, visible flags; deprecated flags excluded); bash -n / zsh -n validated
• Global --quiet — suppresses status/header/section/info/dim; data and errors still print; JSON untouched
• Help examples on 10 top-traffic commands via .addHelpText
• Confirmation prompts on destructive ops (@inquirer/prompts — dead dep now in use): TTY confirm with default No, --force bypass, non-TTY without --force exits 2; cleanup keeps its safe preview flow
• ls/rm aliases on 19 list + 13 delete subcommands via recursive walker

Testing

• 46 new tests (TDD, red-first, injected prompt/isTTY fakes); 797/797; all gates + build clean
• Smokes verified: completion scripts parse, alias help works, --quiet JSON pure, non-TTY delete exit 2 with refusal message

Checklist

• TDD
• Gates green
• Docs + changeset (minor)

Closes #274