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>

Author: jwill824

README.md

@@ -264,6 +264,7 @@ The following community-contributed extensions are available in [`catalog.commun
 | Spec Sync | Detect and resolve drift between specs and implementation. AI-assisted resolution with human approval | `docs` | Read+Write | [spec-kit-sync](https://github.com/bgervin/spec-kit-sync) |
 | Spec Validate | Comprehension validation, review gating, and approval state for spec-kit artifacts — staged quizzes, peer review SLA, and a hard gate before /speckit.implement | `process` | Read+Write | [spec-kit-spec-validate](https://github.com/aeltayeb/spec-kit-spec-validate) |
 | SpecTest | Auto-generate test scaffolds from spec criteria, map coverage, and find untested requirements | `code` | Read+Write | [spec-kit-spectest](https://github.com/Quratulain-bilal/spec-kit-spectest) |
+| Squad Bridge | Bootstrap and synchronize a Squad agent team from your Speckit spec and tasks | `process` | Read+Write | [spec-kit-squad](https://github.com/jwill824/spec-kit-squad) |
 | Staff Review Extension | Staff-engineer-level code review that validates implementation against spec, checks security, performance, and test coverage | `code` | Read-only | [spec-kit-staff-review](https://github.com/arunt14/spec-kit-staff-review) |
 | Status Report | Project status, feature progress, and next-action recommendations for spec-driven workflows | `visibility` | Read-only | [Open-Agent-Tools/spec-kit-status](https://github.com/Open-Agent-Tools/spec-kit-status) |
 | Superpowers Bridge | Orchestrates obra/superpowers skills within the spec-kit SDD workflow across the full lifecycle (clarification, TDD, review, verification, critique, debugging, branch completion) | `process` | Read+Write | [superpowers-bridge](https://github.com/RbBtSn0w/spec-kit-extensions/tree/main/superpowers-bridge) |