feat: add claude-ask-questions preset for AskUserQuestion rendering

Delivers the /speckit.clarify and /speckit.checklist AskUserQuestion
integration as a stackable preset under presets/claude-ask-questions/
instead of modifying core templates or ClaudeIntegration.

- presets/claude-ask-questions/preset.yml registers command overrides
  for speckit.clarify and speckit.checklist following the same pattern
  as the bundled lean preset.
- Override commands replace the Markdown-table question-rendering
  blocks with AskUserQuestion instructions. Option | Description maps
  to {label, description} for clarify; Option | Candidate | Why It
  Matters maps to {label: Candidate, description: Why It Matters} for
  checklist. Recommended option is placed first with a
  "Recommended — <reasoning>" prefix; a final "Custom"/"Short" option
  preserves the free-form ≤5-word escape hatch.
- Registered in presets/catalog.json as a bundled preset.

Core templates, ClaudeIntegration, and the existing test suite are
left untouched, so non-Claude agents and users who do not install
this preset see no behavior change.

Closes #2181

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 0xrafasec

presets/catalog.json

@@ -1,6 +1,6 @@
 {
   "schema_version": "1.0",
-  "updated_at": "2026-04-10T00:00:00Z",
+  "updated_at": "2026-04-13T00:00:00Z",
   "catalog_url": "https://raw.githubusercontent.com/github/spec-kit/main/presets/catalog.json",
   "presets": {
     "lean": {
@@ -17,6 +17,21 @@
         "workflow",
         "core"
       ]
+    },
+    "claude-ask-questions": {
+      "name": "Claude AskUserQuestion",
+      "id": "claude-ask-questions",
+      "version": "1.0.0",
+      "description": "Replaces Markdown-table question rendering in /speckit.clarify and /speckit.checklist with Claude Code's native AskUserQuestion structured picker",
+      "author": "0xrafasec",
+      "repository": "https://github.com/github/spec-kit",
+      "bundled": true,
+      "tags": [
+        "claude",
+        "ask-user-question",
+        "clarify",
+        "checklist"
+      ]
     }
   }
 }