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-mcp-integration/examples/http-server.json

@@ -0,0 +1,20 @@
+{
+  "_comment": "Example HTTP MCP server configuration for REST APIs",
+  "rest-api": {
+    "type": "http",
+    "url": "https://api.example.com/mcp",
+    "headers": {
+      "Authorization": "Bearer ${API_TOKEN}",
+      "Content-Type": "application/json",
+      "X-API-Version": "2024-01-01"
+    }
+  },
+  "internal-service": {
+    "type": "http",
+    "url": "https://api.example.com/mcp",
+    "headers": {
+      "Authorization": "Bearer ${API_TOKEN}",
+      "X-Service-Name": "claude-plugin"
+    }
+  }
+}