fix: use livekit-api package for voice-service token endpoint

The livekit package is the client SDK and doesn't include the server-side
API module. Switch to livekit-api which provides AccessToken, VideoGrants,
RoomAgentDispatch, and RoomConfiguration needed for token generation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/services/voice-service/requirements.txt

@@ -19,4 +19,4 @@ ordered-set
 pypinyin
 cn2an
 jieba
-livekit>=1.0.0
+livekit-api>=1.0.0

packages/services/voice-service/src/api/livekit_token.py

@@ -12,7 +12,7 @@ import uuid
 
 from fastapi import APIRouter, Request
 
-from livekit.api import AccessToken, VideoGrants, RoomAgentDispatch, RoomConfiguration
+from livekit import api as livekit_api
 
 from ..config.settings import settings
 
@@ -32,11 +32,11 @@ async def create_livekit_token(request: Request):
     participant_identity = f"user-{uuid.uuid4().hex[:8]}"
 
     token = (
-        AccessToken(settings.livekit_api_key, settings.livekit_api_secret)
+        livekit_api.AccessToken(settings.livekit_api_key, settings.livekit_api_secret)
         .with_identity(participant_identity)
         .with_name("User")
         .with_grants(
-            VideoGrants(
+            livekit_api.VideoGrants(
                 room_join=True,
                 room=room_name,
                 can_publish=True,
@@ -45,9 +45,9 @@ async def create_livekit_token(request: Request):
             )
         )
         .with_room_config(
-            RoomConfiguration(
+            livekit_api.RoomConfiguration(
                 agents=[
-                    RoomAgentDispatch(
+                    livekit_api.RoomAgentDispatch(
                         agent_name="voice-agent",
                         metadata=json.dumps({"auth_header": auth_header}),
                     )