serving
Mastra-specific glue over the generic @dbx-tools/model toolkit.
The live /serving-endpoints catalogue access, fuzzy name
resolution, and class/fallback selection all live in
@dbx-tools/model; this module only adds what is specific to the
Mastra plugin: pulling a per-request model override off an HTTP
request (header / query / body) and projecting the plugin config
onto the knobs buildModel and the /models route share.