chore(schema): drop orphan features.makima

`lib/state-schema.nix` declared `system.features.makima = false` but
the field was never wired anywhere: no matching option in
core/system/options.nix, no consumer in core/system/state.nix, no
references in the wider tree. Schema-only ghost — removed.

Found during Pillar 8 audit of core/system modules.

lib/state-schema.nix

@@ -50,7 +50,6 @@
       fingerprint = false;
       fido2 = false;
       hybridGPU = false;
-      makima = false;
     };
   };