Fix backend imports and clip pinning flow

backend/app/schemas.py

@@ -67,6 +67,7 @@ class AudioClipUpdate(BaseModel):
     label: str | None = Field(default=None, min_length=1, max_length=255)
     start_ms: int = Field(ge=0)
     end_ms: int = Field(gt=0)
+    sort_order: int | None = None
 
 
 class AudioClipResponse(BaseModel):
@@ -78,6 +79,7 @@ class AudioClipResponse(BaseModel):
     label: str
     start_ms: int
     end_ms: int
+    sort_order: int
     normalization_status: str
     normalized_url: str | None
     waveform_duration_ms: int | None = None
@@ -116,6 +118,12 @@ class GamePrepResponse(BaseModel):
     assignments: list[GameAssignmentResponse]
 
 
+class AudioClipReorder(BaseModel):
+    external_team_id: str
+    owner_external_player_id: str
+    clip_ids: list[int] = Field(min_length=1)
+
+
 class PlaybackSessionCreate(BaseModel):
     external_team_id: str