feat(home-manager): add VS Code and SSH agent integration scripts
- Introduced detect-vscode-for-git script to set VS Code as the editor
- Enhanced ssh-agent-loader to prevent source loops and manage loading
- Updated shell.nix to integrate both scripts for improved user experience
- Also updated packages.nix to add more packages under
my home-manager config
Signed-off-by: Andrei Jiroh Halili <ajhalili2006@andreijiroh.dev>