test(#1749): 旧行为测试适配新口径（目标段长为准/逐处转场重叠/voice_ids 移除）+ filter_complex trim 口径统一

- unified_render_service filter_complex Step1 trim 时长改为 effective-freeze（与直通路径同口径，tpad 补冻结）
- test_duration_compensation / render_audio_utils / render_audio_pure / 两处 render_layer_utils：min(duration,actual) 断言改为目标段长为准
- estimate_total_duration 测试：cut 零重叠、非 cut 逐处扣转场（FakeClip 加 transition_effect/duration）
- test_generation_tasks/preview：voice_ids kwarg/字段移除，配音改 voice_library_id

apps/worker/video_processing/unified_render_service.py

@@ -1736,12 +1736,15 @@ class UnifiedRenderService:
             # trim — 裁剪到指定区间，精确到帧
             effective_duration = UnifiedRenderService._clip_effective_duration(clip)
             trim_start = getattr(clip, "start_time", 0) or 0
+            # #1749 冻结时素材内截取时长 = 目标段长 − freeze（末帧冻结由 tpad 铺满，与直通路径同口径）
+            freeze_seconds = float((clip.config or {}).get("_freeze_seconds", 0.0) or 0.0)
+            trim_dur = max(0.0, effective_duration - freeze_seconds) if freeze_seconds > 0 else effective_duration
 
-            if effective_duration > 0:
+            if trim_dur > 0:
                 if trim_start > 0:
-                    filters.append(f"trim=start={trim_start:.3f}:duration={effective_duration:.3f}")
+                    filters.append(f"trim=start={trim_start:.3f}:duration={trim_dur:.3f}")
                 else:
-                    filters.append(f"trim=duration={effective_duration:.3f}")
+                    filters.append(f"trim=duration={trim_dur:.3f}")
                 filters.append("setpts=PTS-STARTPTS")
 
             # 调速 — 基于 setpts 改变播放速度
@@ -1793,7 +1796,6 @@ class UnifiedRenderService:
             filters.append("setpts=PTS-STARTPTS")
             filters.append(f"fps={self.output_fps}")
             # #1749 末帧冻结：素材短于目标段长时克隆末帧铺满（禁慢放）
-            freeze_seconds = float((clip.config or {}).get("_freeze_seconds", 0.0) or 0.0)
             if freeze_seconds > 0:
                 filters.append(f"tpad=stop_mode=clone:stop_duration={freeze_seconds:.3f}")