docs(readme): list red-team in community-extensions table (#2311)

Follow-up to #2306 (merged). Per maintainer request
(#2306 (comment)),
adds the red-team entry to the alphabetically-ordered community-extensions
table in README.md so the extension is discoverable alongside the other
community entries — not only via catalog.community.json.

Slotted alphabetically between "Reconcile Extension" and "Repository
Index". Category: docs. Effect: Read+Write (produces a structured
findings-report file at specs/<feature-id>/red-team-findings-*.md; does
not modify specs — every resolution is maintainer-authorised).

Co-authored-by: Ash Brener <ashley@midletearth.com>

Author: ashbrener

README.md

@@ -236,6 +236,7 @@ The following community-contributed extensions are available in [`catalog.commun
 | QA Testing Extension | Systematic QA testing with browser-driven or CLI-based validation of acceptance criteria from spec | `code` | Read-only | [spec-kit-qa](https://github.com/arunt14/spec-kit-qa) |
 | Ralph Loop | Autonomous implementation loop using AI agent CLI | `code` | Read+Write | [spec-kit-ralph](https://github.com/Rubiss/spec-kit-ralph) |
 | Reconcile Extension | Reconcile implementation drift by surgically updating feature artifacts. | `docs` | Read+Write | [spec-kit-reconcile](https://github.com/stn1slv/spec-kit-reconcile) |
+| Red Team | Adversarial review of specs before /speckit.plan — parallel lens agents surface risks that clarify/analyze structurally can't (prompt injection, integrity gaps, cross-spec drift, silent failures). Produces a structured findings report; no auto-edits to specs. | `docs` | Read+Write | [spec-kit-red-team](https://github.com/ashbrener/spec-kit-red-team) |
 | Repository Index | Generate index for existing repo for overview, architecture and module level. | `docs` | Read-only | [spec-kit-repoindex](https://github.com/liuyiyu/spec-kit-repoindex) |
 | Retro Extension | Sprint retrospective analysis with metrics, spec accuracy assessment, and improvement suggestions | `process` | Read+Write | [spec-kit-retro](https://github.com/arunt14/spec-kit-retro) |
 | Retrospective Extension | Post-implementation retrospective with spec adherence scoring, drift analysis, and human-gated spec updates | `docs` | Read+Write | [spec-kit-retrospective](https://github.com/emi-dm/spec-kit-retrospective) |