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

scripts/go/sherpa_onnx.go

@@ -398,6 +398,10 @@ type OfflineNemoEncDecCtcModelConfig struct {
 	Model string // Path to the model, e.g., model.onnx or model.int8.onnx
 }
 
+type OfflineZipformerCtcModelConfig struct {
+	Model string // Path to the model, e.g., model.onnx or model.int8.onnx
+}
+
 type OfflineDolphinModelConfig struct {
 	Model string // Path to the model, e.g., model.onnx or model.int8.onnx
 }
@@ -439,16 +443,17 @@ type OfflineLMConfig struct {
 }
 
 type OfflineModelConfig struct {
-	Transducer OfflineTransducerModelConfig
-	Paraformer OfflineParaformerModelConfig
-	NemoCTC    OfflineNemoEncDecCtcModelConfig
-	Whisper    OfflineWhisperModelConfig
-	Tdnn       OfflineTdnnModelConfig
-	SenseVoice OfflineSenseVoiceModelConfig
-	Moonshine  OfflineMoonshineModelConfig
-	FireRedAsr OfflineFireRedAsrModelConfig
-	Dolphin    OfflineDolphinModelConfig
-	Tokens     string // Path to tokens.txt
+	Transducer   OfflineTransducerModelConfig
+	Paraformer   OfflineParaformerModelConfig
+	NemoCTC      OfflineNemoEncDecCtcModelConfig
+	Whisper      OfflineWhisperModelConfig
+	Tdnn         OfflineTdnnModelConfig
+	SenseVoice   OfflineSenseVoiceModelConfig
+	Moonshine    OfflineMoonshineModelConfig
+	FireRedAsr   OfflineFireRedAsrModelConfig
+	Dolphin      OfflineDolphinModelConfig
+	ZipformerCtc OfflineZipformerCtcModelConfig
+	Tokens       string // Path to tokens.txt
 
 	// Number of threads to use for neural network computation
 	NumThreads int
@@ -540,6 +545,7 @@ func newCOfflineRecognizerConfig(config *OfflineRecognizerConfig) *C.struct_Sher
 	c.model_config.fire_red_asr.decoder = C.CString(config.ModelConfig.FireRedAsr.Decoder)
 
 	c.model_config.dolphin.model = C.CString(config.ModelConfig.Dolphin.Model)
+	c.model_config.zipformer_ctc.model = C.CString(config.ModelConfig.ZipformerCtc.Model)
 
 	c.model_config.tokens = C.CString(config.ModelConfig.Tokens)
 
@@ -653,11 +659,22 @@ func freeCOfflineRecognizerConfig(c *C.struct_SherpaOnnxOfflineRecognizerConfig)
 		C.free(unsafe.Pointer(c.model_config.fire_red_asr.encoder))
 		c.model_config.fire_red_asr.encoder = nil
 	}
+
 	if c.model_config.fire_red_asr.decoder != nil {
 		C.free(unsafe.Pointer(c.model_config.fire_red_asr.decoder))
 		c.model_config.fire_red_asr.decoder = nil
 	}
 
+	if c.model_config.dolphin.model != nil {
+		C.free(unsafe.Pointer(c.model_config.dolphin.model))
+		c.model_config.dolphin.model = nil
+	}
+
+	if c.model_config.zipformer_ctc.model != nil {
+		C.free(unsafe.Pointer(c.model_config.zipformer_ctc.model))
+		c.model_config.zipformer_ctc.model = nil
+	}
+
 	if c.model_config.tokens != nil {
 		C.free(unsafe.Pointer(c.model_config.tokens))
 		c.model_config.tokens = nil