Add comprehensive skills, agents, commands collection

- Added 44 external skills from obra/superpowers, ui-ux-pro-max-skill, claude-codex-settings
- Added 8 autonomous agents (commit-creator, pr-creator, pr-reviewer, etc.)
- Added 23 slash commands for Git/GitHub, setup, and plugin development
- Added hooks for code formatting, notifications, and validation
- Added MCP configurations for Azure, GCloud, Supabase, MongoDB, etc.
- Added awesome-openclaw-skills registry (3,002 skills referenced)
- Updated comprehensive README with full documentation

Sources:
- github.com/obra/superpowers (14 skills)
- github.com/nextlevelbuilder/ui-ux-pro-max-skill (1 skill)
- github.com/fcakyon/claude-codex-settings (29 skills, 8 agents, 23 commands)
- github.com/VoltAgent/awesome-openclaw-skills (registry)
- skills.sh (reference)
- buildwithclaude.com (reference)

commands/claude-codex-settings/github-dev-review-pr.md

@@ -0,0 +1,19 @@
+---
+allowed-tools: Task, Read, Grep, Glob
+argument-hint: <PR number or URL>
+description: Review a pull request for code quality and issues
+---
+
+# Review Pull Request
+
+Use the pr-reviewer agent to analyze the pull request and provide a detailed code review.
+
+## PR Reference
+
+$ARGUMENTS
+
+Task(
+description: "Review pull request",
+prompt: "Review the pull request and provide detailed feedback on code quality, potential bugs, and suggestions. PR reference: $ARGUMENTS",
+subagent_type: "github-dev:pr-reviewer"
+)