[ui] Add semantic primitive ownership Build a layered Zenbu token and sizing system, make authored controls use native-underneath primitives, migrate mrjunejune without imposing visual surfaces, and document/enforce HTML ownership in the catalog and wiki. Co-authored-by: Copilot <[email protected]>

# config

Shared Bazel build configurations and platform definitions.

## Usage

Reference in BUILD files:

```starlark
load("//config:defs.bzl", ...)
```