Update Golden Demo extension to v0.3.0

Update golden-demo extension submitted by @jasstt:
- extensions/catalog.community.json (version, download_url, description, provides, tags, updated_at)
- docs/community/extensions.md community extensions table

Closes #3360

Assisted-by: GitHub Copilot (model: claude-sonnet-4.6, autonomous)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

extensions/catalog.community.json

@@ -1,6 +1,6 @@
 {
   "schema_version": "1.0",
-  "updated_at": "2026-07-06T00:00:00Z",
+  "updated_at": "2026-07-07T00:00:00Z",
   "catalog_url": "https://raw.githubusercontent.com/github/spec-kit/main/extensions/catalog.community.json",
   "extensions": {
     "aide": {
@@ -1398,10 +1398,10 @@
     "golden-demo": {
       "name": "Golden Demo",
       "id": "golden-demo",
-      "description": "Extracts acceptance criteria from specs, builds test vectors, and produces a behavioral drift report — complementary to Architecture Guard and CDD.",
+      "description": "Deterministic behavioral drift oracle. Extracts acceptance criteria, generates fuzz test vectors (seed=42), compares golden Python implementations against real code in any language. CI/CD gatekeeper with warn/strict modes.",
       "author": "jasstt",
-      "version": "0.1.1",
-      "download_url": "https://github.com/jasstt/spec-kit-golden-demo/archive/refs/tags/v0.1.1.zip",
+      "version": "0.3.0",
+      "download_url": "https://github.com/jasstt/spec-kit-golden-demo/archive/refs/tags/v0.3.0.zip",
       "repository": "https://github.com/jasstt/spec-kit-golden-demo",
       "homepage": "https://github.com/jasstt/spec-kit-golden-demo",
       "documentation": "https://github.com/jasstt/spec-kit-golden-demo",
@@ -1412,13 +1412,16 @@
         "speckit_version": ">=0.1.0"
       },
       "provides": {
-        "commands": 2,
+        "commands": 3,
         "hooks": 2
       },
       "tags": [
         "testing",
         "drift-detection",
         "behavioral-oracle",
+        "fuzzing",
+        "ci-cd",
+        "cross-language",
         "tdd",
         "quality"
       ],
@@ -1426,7 +1429,7 @@
       "downloads": 0,
       "stars": 0,
       "created_at": "2026-06-24T00:00:00Z",
-      "updated_at": "2026-06-24T00:00:00Z"
+      "updated_at": "2026-07-07T00:00:00Z"
     },
     "harness": {
       "name": "Research Harness",