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

dart-api-examples/non-streaming-asr/run-zipformer-ctc.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+set -ex
+
+dart pub get
+
+if [ ! -f ./sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03/tokens.txt ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/asr-models/sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03.tar.bz2
+
+  tar xvf sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03.tar.bz2
+  rm sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03.tar.bz2
+fi
+
+dart run \
+  ./bin/zipformer-ctc.dart \
+  --model ./sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03/model.int8.onnx \
+  --tokens ./sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03/tokens.txt \
+  --input-wav ./sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03/test_wavs/0.wav