feat: support forwarding options

[spiral-ladder]

zbuild does not support partial arguments. For example, we would not be able to pass only optimize and expect the dependency to be built with the parent's target, which broke building lodestar-z since we were building with portable=true and optimize=.ReleaseFast.

This PR adds that support

[gemini-code-assist]

Code Review

This pull request updates the build runner to preserve user-supplied dependency arguments while automatically filling in missing target and optimize defaults. It also adds validation for the optimize field in module definitions and introduces test fixtures for these scenarios. The review feedback suggests improving compile-time safety by validating the type of the optimize parameter in validateOptimize to prevent cryptic compiler errors. Additionally, it recommends using std.Build.ResolvedTarget instead of std.Target.Query when forwarding the parent's target to maintain consistency and avoid unnecessary target re-resolution.

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[gemini-code-assist]

To ensure consistency with the default dependency configuration (which passes std.Build.ResolvedTarget directly) and to avoid unnecessary target re-resolution in the child dependency, we should use std.Build.ResolvedTarget instead of std.Target.Query when forwarding the parent's target.

    if (!has_target) {
        names[i] = "target";
        types[i] = std.Build.ResolvedTarget;
        attrs[i] = .{};
        i += 1;
    }

[spiral-ladder]

in this case ResolvedTarget contains Target.Query, which is the native target, it's probably more correct to rely on that instead.

[gemini-code-assist]

Following the change to use std.Build.ResolvedTarget in DependencyArgs, we should pass target_parent directly instead of its query representation target_parent.query.

    if (!@hasField(Args, "target")) result.target = target_parent;

[spiral-ladder]

see above for reason to reject ResolvedTarget