Enhance video generation API: add polling URL, video URLs, and error handling; implement polling status endpoint with tests

Co-authored-by: Copilot <copilot@github.com>

backend/tests/test_generate.py

@@ -29,18 +29,15 @@ FAKE_IMAGE = {
 
 FAKE_VIDEO = {
     "id": "gen-vid-1",
-    "model": "stability/stable-video",
+    "polling_url": "https://openrouter.ai/api/v1/videos/gen-vid-1",
     "status": "queued",
-    "video_url": None,
-    "metadata": {"estimated_seconds": 30},
 }
 
 FAKE_VIDEO_DONE = {
     "id": "gen-vid-2",
-    "model": "runway/gen-3",
+    "polling_url": "https://openrouter.ai/api/v1/videos/gen-vid-2",
     "status": "completed",
-    "video_url": "https://example.com/video.mp4",
-    "metadata": None,
+    "unsigned_urls": ["https://example.com/video.mp4"],
 }
 
 
@@ -169,8 +166,8 @@ async def test_generate_video(client):
     data = resp.json()
     assert data["id"] == "gen-vid-1"
     assert data["status"] == "queued"
+    assert data["polling_url"] == "https://openrouter.ai/api/v1/videos/gen-vid-1"
     assert data["video_url"] is None
-    assert data["metadata"]["estimated_seconds"] == 30
 
 
 async def test_generate_video_unauthenticated(client):
@@ -209,6 +206,45 @@ async def test_generate_video_from_image(client):
     data = resp.json()
     assert data["status"] == "completed"
     assert data["video_url"] == "https://example.com/video.mp4"
+    assert data["video_urls"] == ["https://example.com/video.mp4"]
+
+
+async def test_poll_video_status(client):
+    token = await _user_token(client)
+    mock_result = {
+        "id": "gen-vid-1",
+        "status": "completed",
+        "unsigned_urls": ["https://example.com/video.mp4"],
+    }
+    with patch("backend.app.routers.generate.openrouter.poll_video_status", new_callable=AsyncMock, return_value=mock_result):
+        resp = await client.get(
+            "/generate/video/status",
+            params={"polling_url": "https://openrouter.ai/api/v1/videos/gen-vid-1"},
+            headers={"Authorization": f"Bearer {token}"},
+        )
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["status"] == "completed"
+    assert data["video_url"] == "https://example.com/video.mp4"
+
+
+async def test_poll_video_status_unauthenticated(client):
+    resp = await client.get(
+        "/generate/video/status",
+        params={"polling_url": "https://openrouter.ai/api/v1/videos/gen-vid-1"},
+    )
+    assert resp.status_code == 401
+
+
+async def test_poll_video_status_upstream_error(client):
+    token = await _user_token(client)
+    with patch("backend.app.routers.generate.openrouter.poll_video_status", new_callable=AsyncMock, side_effect=Exception("timeout")):
+        resp = await client.get(
+            "/generate/video/status",
+            params={"polling_url": "https://openrouter.ai/api/v1/videos/gen-vid-1"},
+            headers={"Authorization": f"Bearer {token}"},
+        )
+    assert resp.status_code == 502
 
 
 async def test_generate_video_from_image_unauthenticated(client):