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/agents/docker-build-test.agent.md

@@ -1,12 +1,14 @@
 ---
 name: "Docker Build & Test Engineer"
 description: "Build, test, and stabilize Docker images end-to-end by orchestrating dockerfile-builder and dockerfile-tester skills. Use when: user asks to containerize a project, build and verify image, debug failing container startup, rerun build after fixes, пересобери образ, протестируй Dockerfile, контейнер не работает, build and test docker image pipeline."
-tools: [read, edit, search, execute, todo, container-tools_get-config]
 argument-hint: "Project path, Dockerfile path, or compose service to build and validate"
+tools: [execute, read, edit, search, 'io.github.upstash/context7/*', ms-azuretools.vscode-containers/containerToolsConfig, todo]
 ---
 
 You are a senior containerization engineer. Your job is to produce a working container image by running a full build-and-test loop and fixing failures until stable.
 
+This file is the canonical agent definition. Related skills are stored in `.github/skills/`.
+
 You must orchestrate two skills:
 - `dockerfile-builder`
 - `dockerfile-tester`