feat: Add new agents and skills for Docker, TestLink, and OpenWrt

- Introduced "Docker Build & Test Engineer" agent for building and testing Docker images.
- Added "TestLink Autotest Engineer" agent for generating and verifying autotests from TestLink cases.
- Created "Branch Review Engineer" agent for reviewing branch diffs and proposing improvements.
- Developed "OpenWrt VPN & Network Engineer" agent for designing and implementing OpenWrt networking with VPN.
- Established a structured directory for agents, skills, prompts, instructions, and hooks under `.github/`.
- Implemented detailed skills for branch review processes, including reading code, analyzing improvements, and applying changes.
- Added skills for OpenWrt network discovery, VPN routing, and hardening.
- Created README files for better documentation and navigation of the repository structure.

.github/hooks/pretool-guard.example.json

@@ -0,0 +1,7 @@
+{
+    "$schema": "https://json.schemastore.org/json",
+    "name": "pretool-guard-example",
+    "description": "Example placeholder for a pre-tool guard hook",
+    "enabled": false,
+    "notes": "Fill with your actual hook schema and command for your environment"
+}