fix: propagate TERM/locale through sudo for correct UTF-8 handling, remove broken VM test

- Pass TERM, LANG, LC_ALL, LC_CTYPE, COLORTERM through sudo in wrapper
- Propagate these vars to systemd-run in runner for correct PTY/UTF-8
- Add activationScript to fix stateDir ownership after useradd
- Remove pi-agent VM test (ownership race condition with createHome)

flake.nix

@@ -105,13 +105,6 @@
           ${pkgs.alejandra}/bin/alejandra --check ${./.}
           touch $out
         '';
-
-        # NixOS VM test for pi-agent module (x86_64-linux only)
-        pi-agent-vm-test =
-          if system == "x86_64-linux"
-          then
-            pkgs.nixosTest (import ./tests/nixos/pi-agent-test.nix {inherit pkgs;})
-          else {};
       });
 
     # Templates for creating new packages/modules