feat(nix): update secure boot and HALO system configuration

- Set `pkiBundle` in `secureboot` to use `mkDefault` for better configurability.
- Added kernel parameters for HALO, improving performance and boot customization.
- Configured ROCm symlink and switched HALO to `linuxPackages_latest`.

systems/x86_64-linux/halo/default.nix

@@ -10,6 +10,22 @@ with lib.metacfg;
     ./hardware-configuration.nix
     ./xremap.nix
   ];
+  boot.lanzaboote.pkiBundle = "/var/lib/sbctl"; 
+  boot.kernelPackages = lib.mkOverride 0 pkgs.linuxPackages_latest;
+
+  systemd.tmpfiles.rules = 
+  let
+    rocmEnv = pkgs.symlinkJoin {
+      name = "rocm-combined";
+      paths = with pkgs.rocmPackages; [
+        rocblas
+        hipblas
+        clr
+      ];
+    };
+  in [
+    "L+    /opt/rocm   -    -    -     -    ${rocmEnv}"
+  ];
 
   powerManagement.cpuFreqGovernor = "performance";