Fix nested code fence in create-kbe SKILL.md dry-run template

The dry-run draft template used a triple-backtick markdown outer fence
containing inner json/text fences. The first inner closing fence
terminated the outer block, causing the rest of the template to render
as plain markdown. Promote the outer fence to four backticks.

Author: Milos Kotlar

.github/skills/create-kbe/SKILL.md

@@ -192,7 +192,7 @@ issue bodies. Keep them easy to compare and edit on disk.
 
 Prefer this layout for dry-run files:
 
-```markdown
+````markdown
 # Draft KBE issue
 
 - Proposed title: `...`
@@ -226,7 +226,7 @@ Build error leg or test failing: ...
 
 **Recommended action:**
 ...
-```
+````
 
 For dry-run artifacts, prefer the layout above over adding extra sections like
 `Pull request:` or `## Error Details` unless they are truly necessary for