fix schema syntax

app/schemas/models.py

@@ -2,9 +2,8 @@
 Pydantic models for API requests and responses.
 """
 from pydantic import BaseModel, Field
-from typing import Optional
 from enum import Enum
-from typing import List, Optional
+from typing import List, Optional, Dict
 
 
 class ProcessingStatus(str, Enum):
@@ -111,16 +110,16 @@ class TranscriptionResponse(BaseModel):
     """Response containing the transcription results."""
     success: bool = Field(..., description="Whether transcription succeeded")
     message: str = Field(default="", description="Status message")
-    segments: list[TranscriptSegment] = Field(
+    segments: List[TranscriptSegment] = Field(
         default_factory=list,
         description="Transcript segments with speaker and role")
 
     duration: float = Field(default=0.0, description="Audio duration in seconds")
     speaker_count: int = Field(default=0, description="Number of detected speakers")
     processing_time: float = Field(default=0.0, description="Processing time in seconds")
-    speakers: Optional[list[str]] = None
+    speakers: Optional[List[str]] = None
     
-    roles: Optional[dict[str, str]] = Field(
+    roles: Optional[Dict[str, str]] = Field(
         default=None,
         description="Internal mapping speaker_id → role (debug / audit only)"
     )