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

sherpa-onnx/kotlin-api/OfflineRecognizer.kt

@@ -29,6 +29,10 @@ data class OfflineDolphinModelConfig(
     var model: String = "",
 )
 
+data class OfflineZipformerCtcModelConfig(
+    var model: String = "",
+)
+
 data class OfflineWhisperModelConfig(
     var encoder: String = "",
     var decoder: String = "",
@@ -64,6 +68,7 @@ data class OfflineModelConfig(
     var nemo: OfflineNemoEncDecCtcModelConfig = OfflineNemoEncDecCtcModelConfig(),
     var senseVoice: OfflineSenseVoiceModelConfig = OfflineSenseVoiceModelConfig(),
     var dolphin: OfflineDolphinModelConfig = OfflineDolphinModelConfig(),
+    var zipformerCtc: OfflineZipformerCtcModelConfig = OfflineZipformerCtcModelConfig(),
     var teleSpeech: String = "",
     var numThreads: Int = 1,
     var debug: Boolean = false,
@@ -559,6 +564,16 @@ fun getOfflineModelConfig(type: Int): OfflineModelConfig? {
                 modelType = "nemo_transducer",
             )
         }
+
+        31 -> {
+            val modelDir = "sherpa-onnx-zipformer-ctc-zh-int8-2025-07-03"
+            return OfflineModelConfig(
+                zipformerCtc = OfflineZipformerCtcModelConfig(
+                    model = "$modelDir/model.int8.onnx",
+                ),
+                tokens = "$modelDir/tokens.txt",
+            )
+        }
     }
     return null
 }

sherpa-onnx/kotlin-api/OnlineRecognizer.kt

@@ -412,6 +412,7 @@ fun getModelConfig(type: Int): OnlineModelConfig? {
                     model = "$modelDir/model.onnx",
                 ),
                 tokens = "$modelDir/tokens.txt",
+                modelType = "zipformer2",
             )
         }
 
@@ -422,6 +423,7 @@ fun getModelConfig(type: Int): OnlineModelConfig? {
                     model = "$modelDir/model.fp16.onnx",
                 ),
                 tokens = "$modelDir/tokens.txt",
+                modelType = "zipformer2",
             )
         }