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/skills/openwrt-vpn-routing/SKILL.md

@@ -0,0 +1,88 @@
+---
+name: openwrt-vpn-routing
+description: "Design and implement OpenWrt VPN routing with xray/sing-box/WireGuard/OpenVPN, DNS, split tunneling, GeoIP, ASN, and selective tunnel by destination IP. Use when: openwrt vpn routing, policy based routing, split tunneling openwrt, xray routing rules, sing-box route rules, geoip asn tunnel policy."
+argument-hint: "Confirmed topology and tunnel policy from discovery stage"
+---
+
+# OpenWrt VPN Routing
+
+Design and produce concrete configuration for advanced OpenWrt VPN routing.
+
+## Inputs Required
+
+- Discovery summary from `openwrt-network-discovery`
+- Chosen VPN stack and endpoint details
+- Explicit tunnel policy (IP/domain/GeoIP/ASN)
+
+## Procedure
+
+### Step 1 - Select Control Plane
+
+Choose one primary routing controller:
+- `pbr` package for policy-based routing
+- native `ip rule` + custom routing tables
+- service-level route control in xray/sing-box
+
+Document why the selected approach fits the request.
+
+### Step 2 - Build Tunnel and Interface Mapping
+
+Define:
+- tunnel interface lifecycle and startup order
+- firewall zones and forwarding path
+- metric priorities and failover behavior
+
+### Step 3 - Implement Selective Routing
+
+Implement selective tunnel behavior for:
+- static destination IP sets
+- domain groups resolved into nft/ipset targets
+- GeoIP categories
+- ASN-based destination grouping
+
+Ensure LAN bypass and management-plane safety are explicit.
+
+### Step 4 - Configure DNS Path
+
+Set DNS so route policy and resolver path are consistent:
+- resolver selection for tunneled and non-tunneled traffic
+- anti-leak controls
+- optional encrypted DNS
+
+### Step 5 - Produce Config and Commands
+
+Provide practical snippets for:
+- `/etc/config/network`
+- `/etc/config/firewall`
+- `/etc/config/pbr` (if used)
+- xray or sing-box route blocks
+- validation commands
+
+## Validation Checklist
+
+- `ip rule show`
+- `ip route show table <id>`
+- `nft list ruleset`
+- test destination inside and outside tunnel policy
+- DNS resolver path checks
+
+## Output Format
+
+```md
+## VPN Routing Plan
+
+### Architecture
+- ...
+
+### Config Snippets
+- file: ...
+- snippet: ...
+
+### Apply Order
+1. ...
+2. ...
+3. ...
+
+### Validation
+- ...
+```