feat(repo): enrich repo list and add move command

[tyrantkhan]

Summary

Enhance bb repo list with richer metadata and add a bb repo move command.

Motivation

Support repo lifecycle management — specifically identifying stale/archive candidates and moving them between projects. See DEVX-265.

Scope

bb repo list enhancements

• --details flag to include last commit date and open PR count
• Concurrent fetching with bounded parallelism

bb repo move (new command)

• Move a repo to a specified Bitbucket project
• Optional --prefix flag to rename (e.g. --prefix "Archived-")