fix(models): check for all expected ONNX files during conversion

CodeT5 produces multiple ONNX files (encoder_model.onnx and decoder_model.onnx)
but convertToOnnx was only checking for a single model.onnx file. This caused
the conversion step to be marked as complete when the files didn't actually exist,
leading to build failures in the quantization step.

Fix: Use config.files to check for all expected ONNX files based on model type.

Author: jdalton

packages/models/scripts/build.mjs

@@ -156,9 +156,12 @@ async function convertToOnnx(modelKey) {
 
   const config = MODEL_SOURCES[modelKey]
   const modelDir = join(MODELS, modelKey)
-  const onnxPath = join(modelDir, 'model.onnx')
 
-  if (existsSync(onnxPath)) {
+  // Check for expected ONNX files based on model type.
+  const expectedFiles = config.files.filter(f => f.endsWith('.onnx'))
+  const allExist = expectedFiles.every(f => existsSync(join(modelDir, f)))
+
+  if (allExist) {
     logger.success('Already in ONNX format')
     await createCheckpoint(PACKAGE_NAME, `converted-${modelKey}`, { modelKey })
     return