Reorganize Firefox configuration and repository documentation

- Configure Firefox with privacy settings and extensions (Bitwarden, Plasma Integration, MetaMask, Kagi Search, uBlock Origin)
- Set Kagi as default/only search engine
- Add MOZ_USE_XINPUT2=1 for smooth scrolling
- Create context/ directory for concise unit documentation
- Create tests/ directory for test scripts
- Move test-firefox-config.sh to tests/
- Update agents.md with documentation workflow guidelines
- Fix syntax errors in desktop.nix and dev.nix

desktop/dev.nix

@@ -1,4 +1,4 @@
-{ config, pkgs, pkgs-unstable, lib, octofriend, ... }:
+{ config, pkgs, pkgs-unstable, lib, ... }:
 
 {
 
@@ -6,8 +6,8 @@
    (python3.withPackages(ps: with ps; [ pandas requests python-dotenv pip uv ]))
   nodejs
   putty                   # SSH/Telnet client
-  octofriend.packages.${pkgs.system}.default
-  ];
+  # octofriend.packages.${pkgs.system}.default
+];
 
   programs.nix-ld.enable = true;