Fix lanes init: DEFAULT_REGISTRIES maps kind -> single renderer

spi/renderers/registry.py

@@ -32,7 +32,8 @@ class ModelRouter:
             raise ValueError(f"unknown SPI_MODE '{mode}'; expected mock|small|production")
         self.mode = mode
         self._lanes: dict[str, dict[str, Renderer]] = {
-            kind: dict(lanes) for kind, lanes in DEFAULT_REGISTRIES[mode].items()
+            kind: {renderer.name: renderer}
+            for kind, renderer in DEFAULT_REGISTRIES[mode].items()
         }
 
     def register(self, kind: str, renderer: Renderer) -> None: