feat(agent): support multimodal intent input and ASR transcribe endpoint

backend/src/v1/agent/router.py

@@ -5,12 +5,12 @@ import asyncio
 from datetime import date
 import re
 import time
-from typing import Annotated
+from typing import Annotated, Union
 
 from ag_ui.core import RunAgentInput
-from fastapi import APIRouter, Depends, Header, Query, Request, status
+from fastapi import APIRouter, Depends, Header, Query, Request, status, UploadFile
 from fastapi import HTTPException
-from fastapi.responses import StreamingResponse
+from fastapi.responses import JSONResponse, StreamingResponse
 
 from core.agent.infrastructure.agui.stream import to_sse_event
 from core.agent.domain.agui_input import (
@@ -20,8 +20,8 @@ from core.agent.domain.agui_input import (
 from core.auth.models import CurrentUser
 from services.base.redis import get_or_init_redis_client
 from v1.agent.dependencies import get_agent_service
-from v1.agent.schemas import TaskAcceptedResponse
-from v1.agent.service import AgentService
+from v1.agent.schemas import AsrTranscribeResponse, TaskAcceptedResponse
+from v1.agent.service import AgentService, asr_service
 from v1.users.dependencies import get_current_user
 
 router = APIRouter(prefix="/agent", tags=["agent"])
@@ -211,3 +211,35 @@ async def get_user_history_snapshot(
         thread_id=thread_id,
         before=before,
     )
+
+
+@router.post(
+    "/transcribe",
+    response_model=AsrTranscribeResponse,
+    status_code=status.HTTP_200_OK,
+)
+async def transcribe(
+    audio: UploadFile,
+    current_user: Annotated[CurrentUser, Depends(get_current_user)],
+) -> Union[AsrTranscribeResponse, JSONResponse]:
+    try:
+        audio_data = await audio.read()
+        if not audio_data:
+            raise ValueError("Empty audio file")
+
+        transcript = await asr_service.transcribe(
+            audio_data, audio.filename or "unknown"
+        )
+
+        return AsrTranscribeResponse(transcript=transcript)
+
+    except ValueError as exc:
+        return JSONResponse(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            content={"detail": str(exc)},
+        )
+    except RuntimeError as exc:
+        return JSONResponse(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            content={"detail": str(exc)},
+        )