Add Volcengine support for TTS and ASR services

- Introduced Volcengine as a new provider for both TTS and ASR services.
- Updated configuration files to include Volcengine-specific parameters such as app_id, resource_id, and uid.
- Enhanced the ASR service to support streaming mode with Volcengine's API.
- Modified existing tests to validate the integration of Volcengine services.
- Updated documentation to reflect the addition of Volcengine as a supported provider for TTS and ASR.
- Refactored service factory to accommodate Volcengine alongside existing providers.

engine/tests/test_volcengine_asr_provider.py

@@ -0,0 +1,86 @@
+import gzip
+import json
+
+from providers.asr.volcengine import VolcengineRealtimeASRService
+
+
+def test_volcengine_seed_protocol_defaults_and_headers():
+    service = VolcengineRealtimeASRService(
+        api_key="access-token",
+        api_url="wss://openspeech.bytedance.com/api/v3/sauc/bigmodel",
+        app_id="app-1",
+        uid="caller-1",
+    )
+
+    assert service.protocol == "seed"
+    assert service.resource_id == "volc.bigasr.sauc.duration"
+
+    headers = service._build_seed_headers("req-1")
+    assert headers == {
+        "X-Api-App-Key": "app-1",
+        "X-Api-Access-Key": "access-token",
+        "X-Api-Resource-Id": "volc.bigasr.sauc.duration",
+        "X-Api-Request-Id": "req-1",
+    }
+
+
+def test_volcengine_seed_start_payload_merges_request_params():
+    service = VolcengineRealtimeASRService(
+        api_key="access-token",
+        api_url="wss://openspeech.bytedance.com/api/v3/sauc/bigmodel",
+        app_id="app-1",
+        uid="caller-1",
+        language="zh-CN",
+        request_params={
+            "request": {
+                "end_window_size": 800,
+                "force_to_speech_time": 1000,
+                "context": "{\"hotwords\":[{\"word\":\"doubao\"}]}",
+            },
+            "audio": {"codec": "raw"},
+        },
+    )
+
+    payload = service._build_seed_start_payload()
+    assert payload["user"] == {"uid": "caller-1"}
+    assert payload["audio"] == {
+        "format": "pcm",
+        "rate": 16000,
+        "bits": 16,
+        "channels": 1,
+        "codec": "raw",
+        "language": "zh-CN",
+    }
+    assert payload["request"]["model_name"] == "bigmodel"
+    assert payload["request"]["end_window_size"] == 800
+    assert payload["request"]["force_to_speech_time"] == 1000
+    assert payload["request"]["context"] == "{\"hotwords\":[{\"word\":\"doubao\"}]}"
+
+
+def test_volcengine_seed_start_request_encodes_gzip_json_payload():
+    service = VolcengineRealtimeASRService(
+        api_key="access-token",
+        api_url="wss://openspeech.bytedance.com/api/v3/sauc/bigmodel",
+        app_id="app-1",
+        uid="caller-1",
+    )
+
+    frame = service._build_seed_start_request()
+    assert frame[0] == 0x11
+    assert frame[1] == 0x11
+
+    payload_length = int.from_bytes(frame[8:12], "big")
+    payload = json.loads(gzip.decompress(frame[12 : 12 + payload_length]).decode("utf-8"))
+    assert payload["user"]["uid"] == "caller-1"
+    assert payload["request"]["model_name"] == "bigmodel"
+
+
+def test_volcengine_gateway_protocol_keeps_model_query():
+    service = VolcengineRealtimeASRService(
+        api_key="access-token",
+        api_url="wss://ai-gateway.vei.volces.com/v1/realtime",
+        model="bigmodel",
+    )
+
+    assert service.protocol == "gateway"
+    assert service.api_url == "wss://ai-gateway.vei.volces.com/v1/realtime?model=bigmodel"