feat(nix): overhaul nix flake and packages (#9032)

packages/opencode/script/build.ts

@@ -90,6 +90,11 @@ const targets = singleFlag
         return baselineFlag
       }
 
+      // also skip abi-specific builds for the same reason
+      if (item.abi !== undefined) {
+        return false
+      }
+
       return true
     })
   : allTargets