Support non-streaming zipformer CTC ASR models (#2340)

This PR adds support for non-streaming Zipformer CTC ASR models across 
multiple language bindings, WebAssembly, examples, and CI workflows.

- Introduces a new OfflineZipformerCtcModelConfig in C/C++, Python, Swift, Java, Kotlin, Go, Dart, Pascal, and C# APIs
- Updates initialization, freeing, and recognition logic to include Zipformer CTC in WASM and Node.js
- Adds example scripts and CI steps for downloading, building, and running Zipformer CTC models

Model doc is available at
https://k2-fsa.github.io/sherpa/onnx/pretrained_models/offline-ctc/icefall/zipformer.html

.github/scripts/test-dart.sh

@@ -6,6 +6,10 @@ cd dart-api-examples
 
 pushd non-streaming-asr
 
+echo '----------Zipformer CTC----------'
+./run-zipformer-ctc.sh
+rm -rf sherpa-onnx-*
+
 echo '----------SenseVoice----------'
 ./run-sense-voice-with-hr.sh
 ./run-sense-voice.sh
@@ -114,6 +118,10 @@ popd
 
 pushd vad-with-non-streaming-asr
 
+echo '----------Zipformer CTC----------'
+./run-zipformer-ctc.sh
+rm -rf sherpa-onnx-*
+
 echo '----------Dolphin CTC----------'
 ./run-dolphin-ctc.sh
 rm -rf sherpa-onnx-*