Add Sarvam LLM, update Sarvam STT models, expose usage_info on run detail (#351)

* Add Sarvam LLM provider, update Sarvam STT models, expose usage_info on run detail.
Depends on pipecat PR dograh-hq/pipecat#43 for STT string language support.
Submodule bump will follow after that merges.

* test: cover Sarvam STT language mapping; link Sarvam docs

---------

Co-authored-by: Sabiha Khan <sabihak89@gmail.com>

api/tests/test_run_usage_response.py

@@ -0,0 +1,23 @@
+from api.services.pricing.run_usage_response import format_public_usage_info
+
+
+def test_format_public_usage_info():
+    usage_info = {
+        "llm": {
+            "SarvamLLMService#0|||sarvam-30b": {
+                "prompt_tokens": 100,
+                "completion_tokens": 50,
+                "total_tokens": 150,
+            }
+        },
+        "tts": {"ElevenLabsTTSService#0|||eleven_flash_v2_5": 42},
+        "stt": {},
+        "call_duration_seconds": 12.4,
+    }
+
+    result = format_public_usage_info(usage_info)
+
+    assert result["llm"]["SarvamLLMService#0|||sarvam-30b"]["prompt_tokens"] == 100
+    assert result["tts"]["ElevenLabsTTSService#0|||eleven_flash_v2_5"] == 42
+    assert result["stt"] == {}
+    assert result["call_duration_seconds"] == 12.4

api/tests/test_sarvam_service_factory.py

@@ -0,0 +1,114 @@
+from types import SimpleNamespace
+from unittest.mock import patch
+
+import pytest
+from pipecat.services.sarvam.llm import SarvamLLMService as RealSarvamLLMService
+from pipecat.transcriptions.language import Language
+
+from api.services.configuration.registry import (
+    SarvamLLMConfiguration,
+    ServiceProviders,
+)
+from api.services.pipecat.audio_config import AudioConfig
+from api.services.pipecat.service_factory import (
+    create_llm_service,
+    create_llm_service_from_provider,
+    create_stt_service,
+)
+
+
+class TestSarvamLLMConfiguration:
+    def test_default_values(self):
+        config = SarvamLLMConfiguration(api_key="test-key")
+        assert config.provider == ServiceProviders.SARVAM
+        assert config.model == "sarvam-30b"
+        assert config.temperature == 0.5
+
+    def test_custom_model(self):
+        config = SarvamLLMConfiguration(api_key="test-key", model="sarvam-105b")
+        assert config.model == "sarvam-105b"
+
+
+class TestSarvamLLMServiceFactory:
+    def test_create_sarvam_llm_service(self):
+        with patch(
+            "api.services.pipecat.service_factory.SarvamLLMService"
+        ) as mock_service:
+            mock_service.Settings = RealSarvamLLMService.Settings
+            create_llm_service_from_provider(
+                provider=ServiceProviders.SARVAM.value,
+                model="sarvam-30b",
+                api_key="test-key",
+            )
+
+        assert mock_service.call_count == 1
+        kwargs = mock_service.call_args.kwargs
+        assert kwargs["api_key"] == "test-key"
+        assert kwargs["settings"].model == "sarvam-30b"
+        assert kwargs["settings"].temperature == 0.5
+
+    def test_create_sarvam_llm_service_passes_user_temperature(self):
+        with patch(
+            "api.services.pipecat.service_factory.SarvamLLMService"
+        ) as mock_service:
+            mock_service.Settings = RealSarvamLLMService.Settings
+            create_llm_service_from_provider(
+                provider=ServiceProviders.SARVAM.value,
+                model="sarvam-30b",
+                api_key="test-key",
+                temperature=0.8,
+            )
+
+        kwargs = mock_service.call_args.kwargs
+        assert kwargs["settings"].temperature == 0.8
+
+    def test_create_llm_service_extracts_sarvam_temperature(self):
+        user_config = SimpleNamespace(
+            llm=SimpleNamespace(
+                provider=ServiceProviders.SARVAM.value,
+                model="sarvam-30b",
+                api_key="test-key",
+                temperature=0.7,
+            )
+        )
+
+        with patch(
+            "api.services.pipecat.service_factory.SarvamLLMService"
+        ) as mock_service:
+            mock_service.Settings = RealSarvamLLMService.Settings
+            create_llm_service(user_config)
+
+        kwargs = mock_service.call_args.kwargs
+        assert kwargs["settings"].temperature == 0.7
+
+
+class TestSarvamSTTServiceFactory:
+    @pytest.mark.parametrize(
+        "input_language,expected_language",
+        [
+            ("unknown", None),
+            (None, None),
+            ("hi-IN", Language.HI_IN),
+            ("ne-IN", "ne-IN"),
+        ],
+    )
+    def test_stt_language_mapping(self, input_language, expected_language):
+        user_config = SimpleNamespace(
+            stt=SimpleNamespace(
+                provider=ServiceProviders.SARVAM.value,
+                model="saaras:v3",
+                api_key="test-key",
+                language=input_language,
+            )
+        )
+        audio_config = AudioConfig(
+            transport_in_sample_rate=16000, transport_out_sample_rate=16000
+        )
+
+        with patch(
+            "api.services.pipecat.service_factory.SarvamSTTService"
+        ) as mock_service:
+            create_stt_service(user_config, audio_config)
+
+        kwargs = mock_service.call_args.kwargs
+        assert kwargs["settings"].language == expected_language