Marker DSL extension that pairs with Lavash.Dsl to make
layer-2-only modules reject layer-4 features at compile time.
Adds a single transformer, Lavash.Transformers.ValidateBase,
which fires only when the module sets
@__lavash_layer__ :base (done automatically by
Lavash.LiveView.Base / Lavash.Component.Base).
The transformer rejects any optimistic: true, animated: ...,
or calculate ..., optimistic: true usage with a friendly
compile-time error explaining the layering choice.
Why this lives in its own extension
Spark assembles a module's effective transformer pipeline by
unioning the transformers from each listed extension. We can't
edit Lavash.Dsl's transformer list at use-site, so Base
ships an extra extension that adds the strict-mode check
alongside the standard pipeline.