fix: add allowed-tools frontmatter so AskUserQuestion works in Claude Code

In newer versions of Claude Code, tools like AskUserQuestion are not
available to skills unless explicitly listed in the allowed-tools
frontmatter field. Without it, the skill cannot prompt users with
multiple-choice questions during the presentation design phase.

Differs from PR #37: that PR only clarifies text — this PR adds the
required YAML frontmatter that Claude Code enforces at the runtime level.

SKILL.md

@@ -1,6 +1,7 @@
 ---
 name: frontend-slides
 description: Create stunning, animation-rich HTML presentations from scratch or by converting PowerPoint files. Use when the user wants to build a presentation, convert a PPT/PPTX to web, or create slides for a talk/pitch. Helps non-designers discover their aesthetic through visual exploration rather than abstract choices.
+allowed-tools: Read, Write, Edit, Bash, AskUserQuestion
 ---
 
 # Frontend Slides