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)

skills/external/plugin-dev-hook-development/examples/validate-bash.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+# Example PreToolUse hook for validating Bash commands
+# This script demonstrates bash command validation patterns
+
+set -euo pipefail
+
+# Read input from stdin
+input=$(cat)
+
+# Extract command
+command=$(echo "$input" | jq -r '.tool_input.command // empty')
+
+# Validate command exists
+if [ -z "$command" ]; then
+  echo '{"continue": true}' # No command to validate
+  exit 0
+fi
+
+# Check for obviously safe commands (quick approval)
+if [[ "$command" =~ ^(ls|pwd|echo|date|whoami)(\s|$) ]]; then
+  exit 0
+fi
+
+# Check for destructive operations
+if [[ "$command" == *"rm -rf"* ]] || [[ "$command" == *"rm -fr"* ]]; then
+  echo '{"hookSpecificOutput": {"permissionDecision": "deny"}, "systemMessage": "Dangerous command detected: rm -rf"}' >&2
+  exit 2
+fi
+
+# Check for other dangerous commands
+if [[ "$command" == *"dd if="* ]] || [[ "$command" == *"mkfs"* ]] || [[ "$command" == *"> /dev/"* ]]; then
+  echo '{"hookSpecificOutput": {"permissionDecision": "deny"}, "systemMessage": "Dangerous system operation detected"}' >&2
+  exit 2
+fi
+
+# Check for privilege escalation
+if [[ "$command" == sudo* ]] || [[ "$command" == su* ]]; then
+  echo '{"hookSpecificOutput": {"permissionDecision": "ask"}, "systemMessage": "Command requires elevated privileges"}' >&2
+  exit 2
+fi
+
+# Approve the operation
+exit 0