Add SpecAssay Check extension to community catalog (#4113)

Add specassay-check extension submitted by @rdryfoos to:
- extensions/catalog.community.json (alphabetical order)
- docs/community/extensions.md community extensions table

Closes #4057

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Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
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docs/community/extensions.md

@@ -146,6 +146,7 @@ The following community-contributed extensions are available in [`catalog.commun
 | 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) |
 | Spec-Kit BDD | ATDD/BDD extension: convert specs to Gherkin scenarios, scaffold step definitions, and verify acceptance test coverage | `process` | Read+Write | [spec-kit-bdd](https://github.com/RSginer/spec-kit-bdd) |
 | Spec2Cloud | Spec-driven workflow tuned for shipping to Azure | `process` | Read+Write | [spec2cloud](https://github.com/Azure-Samples/Spec2Cloud) |
+| SpecAssay Check | Gate 2 refuses silent gaps and emits a trace-manifest (trace-manifest.json). | `visibility` | Read+Write | [specassay](https://github.com/rdryfoos/specassay) |
 | SpecJudge — right-size the model before you implement | Recommends the model that fits your tasks, citing the spec fragment behind every level. | `process` | Read-only | [SpecJudge](https://github.com/JoaquinRuiz/SpecJudge) |
 | SpecKit Companion | Live spec-driven progress — lifecycle capture, status, resume, and a turbo pipeline profile | `visibility` | Read+Write | [speckit-companion](https://github.com/alfredoperez/speckit-companion) |
 | SpecKit Grill Me | Exhaustively resolve specification ambiguities and decisions before planning | `process` | Read+Write | [speckit-grill-me](https://github.com/yoshi1220/speckit-grill-me) |

extensions/catalog.community.json

@@ -4186,6 +4186,44 @@
       "created_at": "2026-04-30T00:00:00Z",
       "updated_at": "2026-04-30T00:00:00Z"
     },
+    "specassay-check": {
+      "name": "SpecAssay Check",
+      "id": "specassay-check",
+      "description": "Gate 2 refuses silent gaps and emits a trace-manifest (trace-manifest.json).",
+      "author": "Rik Dryfoos",
+      "version": "0.3.3",
+      "download_url": "https://github.com/rdryfoos/specassay/releases/download/v0.3.3/specassay-check-0.3.3.zip",
+      "repository": "https://github.com/rdryfoos/specassay",
+      "homepage": "https://www.specassay.com",
+      "documentation": "https://github.com/rdryfoos/specassay/blob/main/extensions/specassay-check/README.md",
+      "changelog": "https://github.com/rdryfoos/specassay/blob/main/CHANGELOG.md",
+      "license": "MIT",
+      "category": "visibility",
+      "effect": "read-write",
+      "requires": {
+        "speckit_version": ">=0.14.0",
+        "tools": [
+          { "name": "bash", "required": true },
+          { "name": "python3", "version": ">=3.8", "required": true }
+        ]
+      },
+      "provides": {
+        "commands": 1,
+        "hooks": 1
+      },
+      "tags": [
+        "traceability",
+        "gate",
+        "ci",
+        "governance",
+        "sdd"
+      ],
+      "verified": false,
+      "downloads": 0,
+      "stars": 0,
+      "created_at": "2026-08-13T00:00:00Z",
+      "updated_at": "2026-08-13T00:00:00Z"
+    },
     "specjudge": {
       "name": "SpecJudge — right-size the model before you implement",
       "id": "specjudge",