feat: add spec-kit-onboard extension to community catalog

Adds the onboard extension (v2.1.0) — contextual onboarding and
progressive growth for developers new to spec-kit projects.

- 7 commands: start, explain, trail, quiz, badge, mentor, team
- 3 hooks: after-implement, before-implement, after-explain
- Repository: https://github.com/dmux/spec-kit-onboard

Author: dmux

README.md

@@ -181,6 +181,7 @@ The following community-contributed extensions are available in [`catalog.commun
 | Iterate | Iterate on spec documents with a two-phase define-and-apply workflow — refine specs mid-implementation and go straight back to building | `docs` | Read+Write | [spec-kit-iterate](https://github.com/imviancagrace/spec-kit-iterate) |
 | Jira Integration | Create Jira Epics, Stories, and Issues from spec-kit specifications and task breakdowns with configurable hierarchy and custom field support | `integration` | Read+Write | [spec-kit-jira](https://github.com/mbachorik/spec-kit-jira) |
 | Learning Extension | Generate educational guides from implementations and enhance clarifications with mentoring context | `docs` | Read+Write | [spec-kit-learn](https://github.com/imviancagrace/spec-kit-learn) |
+| Onboard | Contextual onboarding and progressive growth for developers new to spec-kit projects. Explains specs, maps dependencies, validates understanding, and guides the next step | `process` | Read+Write | [spec-kit-onboard](https://github.com/dmux/spec-kit-onboard) |
 | Plan Review Gate | Require spec.md and plan.md to be merged via MR/PR before allowing task generation | `process` | Read-only | [spec-kit-plan-review-gate](https://github.com/luno/spec-kit-plan-review-gate) |
 | Presetify | Create and validate presets and preset catalogs | `process` | Read+Write | [presetify](https://github.com/mnriem/spec-kit-extensions/tree/main/presetify) |
 | Project Health Check | Diagnose a Spec Kit project and report health issues across structure, agents, features, scripts, extensions, and git | `visibility` | Read-only | [spec-kit-doctor](https://github.com/KhawarHabibKhan/spec-kit-doctor) |

extensions/catalog.community.json

@@ -437,6 +437,39 @@
       "created_at": "2026-03-05T00:00:00Z",
       "updated_at": "2026-03-05T00:00:00Z"
     },
+    "onboard": {
+      "name": "Onboard",
+      "id": "onboard",
+      "description": "Contextual onboarding and progressive growth for developers new to spec-kit projects. Explains specs, maps dependencies, validates understanding, and guides the next step.",
+      "author": "Rafael Sales",
+      "version": "2.1.0",
+      "download_url": "https://github.com/dmux/spec-kit-onboard/archive/refs/tags/v2.1.0.zip",
+      "repository": "https://github.com/dmux/spec-kit-onboard",
+      "homepage": "https://github.com/dmux/spec-kit-onboard",
+      "documentation": "https://github.com/dmux/spec-kit-onboard/blob/main/README.md",
+      "changelog": "https://github.com/dmux/spec-kit-onboard/blob/main/CHANGELOG.md",
+      "license": "MIT",
+      "requires": {
+        "speckit_version": ">=0.1.0"
+      },
+      "provides": {
+        "commands": 7,
+        "hooks": 3
+      },
+      "tags": [
+        "onboarding",
+        "learning",
+        "mentoring",
+        "developer-experience",
+        "gamification",
+        "knowledge-transfer"
+      ],
+      "verified": false,
+      "downloads": 0,
+      "stars": 0,
+      "created_at": "2026-03-26T00:00:00Z",
+      "updated_at": "2026-03-26T00:00:00Z"
+    },
     "plan-review-gate": {
       "name": "Plan Review Gate",
       "id": "plan-review-gate",