[Infra] Restructure repository to isolate agent service

[kox13]

Issue

Currently, the repository root contains build system configuration and artifacts that are only used by the agent service, including:

• CMakeLists.txt
• libs/ directory
• build/ directory

This structure exists due to the original assumption that both the server and agent would be implemented in C++. However, only the agent is currently using the C++ toolchain.

As a result, the repository structure is misleading and tightly coupled to a single service, which reduces clarity and scalability.

Proposal

• Move CMakeLists.txt into sources/agent and consolidate it with sources/agent/CMakeLists.txt
• After above change build should already be created in sources/agent
• Move libs into sources/agent
• Update all affected paths in:
  • CMake configuration
  • GitHub Actions workflows
  • vcpkg integration
  • any scripts referencing old paths