docs: add missing PermissionRequest hook event

Add PermissionRequest to the hook events list in plugin-structure skill
and README. This event fires when a permission dialog is shown and was
missing from the documentation despite being in the official Claude Code
reference.

Fixes #85

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: sjnims

README.md

@@ -60,7 +60,7 @@ Use this workflow for structured, high-quality plugin development from concept t
 **What it covers:**
 - Prompt-based hooks (recommended) with LLM decision-making
 - Command hooks for deterministic validation
-- All hook events: PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification
+- All hook events: PreToolUse, PermissionRequest, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification
 - Hook output formats and JSON schemas
 - Security best practices and input validation
 - ${CLAUDE_PLUGIN_ROOT} for portable paths

plugins/plugin-dev/skills/plugin-structure/SKILL.md

@@ -235,7 +235,7 @@ hooks/
 }
 ```
 
-**Available events**: PreToolUse, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification
+**Available events**: PreToolUse, PermissionRequest, PostToolUse, Stop, SubagentStop, SessionStart, SessionEnd, UserPromptSubmit, PreCompact, Notification
 
 **Usage**: Hooks execute automatically in response to Claude Code events