feat: add Squad Bridge extension to community catalog (#2417)

* feat: add squad bridge extension to community catalog

Adds spec-kit-squad by jwill824 — a Spec Kit extension that bootstraps
and synchronizes a Squad agent team from your Speckit spec and tasks.

- 4 commands: init, generate, route, status
- 2 hooks: after_specify (generate), after_tasks (route)
- v1.0.0 release

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* chore: add requires.tools for squad-cli in catalog entry

* Update extensions/catalog.community.json

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>