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/prompts/README.md

@@ -0,0 +1,11 @@
+# Prompts
+
+Store reusable prompt files here with the pattern:
+
+- `<name>.prompt.md`
+
+Each prompt should contain:
+- clear `description`
+- optional `argument-hint`
+- selected `agent` when specialization is required
+- focused single-task body

.github/prompts/openwrt-vpn-setup.prompt.md

@@ -0,0 +1,28 @@
+---
+name: "OpenWrt VPN Setup"
+description: "Plan and implement OpenWrt VPN with selective routing, DNS, GeoIP/ASN, and split tunneling using the OpenWrt VPN & Network Engineer agent."
+argument-hint: "Router/OpenWrt version, VPN type (xray/sing-box/WireGuard/OpenVPN), which IPs/domains should go via VPN, DNS requirements"
+agent: "OpenWrt VPN & Network Engineer"
+---
+
+Create a complete OpenWrt VPN plan and implementation guidance from the provided input.
+
+Requirements:
+- Support xray, sing-box, WireGuard, or OpenVPN (choose and justify)
+- Configure DNS with leak prevention
+- Configure split tunneling and policy-based routing
+- Route VPN only for selected destination IPs and/or domain groups
+- If requested, include GeoIP and ASN based routing policies
+- Provide concrete OpenWrt config snippets and apply order
+- Provide verification commands and rollback steps
+
+Before integration work, request missing MCP/webhook details:
+- MCP server IDs and intended actions
+- webhook URL/method/auth/headers/payload
+- secret handling and retry/error policy
+
+Output in sections:
+1. Discovery Summary
+2. VPN Routing Plan
+3. Hardening and Validation
+4. Open Questions