fix: align Freepik API paths with OpenAPI spec

The original implementation used guessed endpoint paths that don't match
the actual Freepik API. Key fixes based on their OpenAPI spec:

- Task polling is per-endpoint (e.g. GET /v1/ai/text-to-image/flux-dev/{task-id})
  not a generic /v1/ai/tasks/{id}. freepik_client now returns TaskResult
  with status_path, and task_tracker polls using that path.
- Fixed endpoint paths: flux-pro -> flux-pro-v1-1, upscale -> image-upscaler,
  relight -> image-relight, style-transfer -> image-style-transfer,
  expand -> image-expand/flux-pro, inpaint -> ideogram-image-edit,
  remove-background -> beta/remove-background, classifier -> classifier/image,
  audio-isolate -> audio-isolation, icon -> text-to-icon
- Fixed video paths: kling -> kling-o1-pro with kling-o1 status path,
  minimax -> minimax-hailuo-02-1080p, seedance -> seedance-pro-1080p
- Fixed request schemas to match actual API params (e.g. scale_factor
  not scale, reference_image not style_reference, image_url for bg removal)
- Fixed response parsing: status is uppercase (COMPLETED not completed),
  results in data.generated[] array, classifier returns [{class_name, probability}]

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

app/routers/video_generation.py

@@ -6,30 +6,26 @@ from fastapi import APIRouter, HTTPException
 from app.schemas.common import TaskResponse, TaskStatus
 from app.schemas.video_generation import KlingRequest, MinimaxRequest, SeedanceRequest
 from app.services import freepik_client, task_tracker
+from app.services.freepik_client import _extract_task_id
 
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix='/api/v1/generate/video', tags=['video-generation'])
 
 
-def _extract_task_id(result: dict) -> str:
-    data = result.get('data', result)
-    freepik_task_id = str(data.get('task_id') or data.get('id', ''))
-    if not freepik_task_id:
-        raise HTTPException(status_code=502, detail='No task_id in Freepik response')
-    return freepik_task_id
-
-
 @router.post('/kling', response_model=TaskResponse)
 async def generate_video_kling(request: KlingRequest):
     result = await freepik_client.generate_video_kling(
-        image=request.image,
+        first_frame=request.first_frame,
+        last_frame=request.last_frame,
         prompt=request.prompt,
         duration=request.duration,
         aspect_ratio=request.aspect_ratio,
     )
-    freepik_id = _extract_task_id(result)
-    internal_id = task_tracker.submit(freepik_id, {'model': 'kling'})
+    freepik_id = _extract_task_id(result.data)
+    if not freepik_id:
+        raise HTTPException(status_code=502, detail='No task_id in Freepik response')
+    internal_id = task_tracker.submit(freepik_id, result.status_path, {'model': 'kling'})
     return TaskResponse(
         task_id=internal_id,
         status=TaskStatus.pending,
@@ -42,10 +38,12 @@ async def generate_video_minimax(request: MinimaxRequest):
     result = await freepik_client.generate_video_minimax(
         prompt=request.prompt,
         first_frame_image=request.first_frame_image,
-        subject_reference=request.subject_reference,
+        last_frame_image=request.last_frame_image,
     )
-    freepik_id = _extract_task_id(result)
-    internal_id = task_tracker.submit(freepik_id, {'model': 'minimax'})
+    freepik_id = _extract_task_id(result.data)
+    if not freepik_id:
+        raise HTTPException(status_code=502, detail='No task_id in Freepik response')
+    internal_id = task_tracker.submit(freepik_id, result.status_path, {'model': 'minimax'})
     return TaskResponse(
         task_id=internal_id,
         status=TaskStatus.pending,
@@ -59,10 +57,11 @@ async def generate_video_seedance(request: SeedanceRequest):
         prompt=request.prompt,
         image=request.image,
         duration=request.duration,
-        resolution=request.resolution,
     )
-    freepik_id = _extract_task_id(result)
-    internal_id = task_tracker.submit(freepik_id, {'model': 'seedance'})
+    freepik_id = _extract_task_id(result.data)
+    if not freepik_id:
+        raise HTTPException(status_code=502, detail='No task_id in Freepik response')
+    internal_id = task_tracker.submit(freepik_id, result.status_path, {'model': 'seedance'})
     return TaskResponse(
         task_id=internal_id,
         status=TaskStatus.pending,