refactor(wave110): 抽离pip_config领域模型 + 64单测

- 新建 packages/domain/pip_config.py：PiPLayerConfig/PiPConfig 数据类 +
  parse_size_value/calculate_pip_position 纯逻辑函数 + 9位置+6动画常量
- pip_engine.py: 509→357行 (-152行, -30%)，复用 pip_config 的类和函数
  保留模块级导出与类方法薄包装，完全向后兼容
- 新增 64 个单测覆盖数据模型 + 纯逻辑函数

apps/worker/video_processing/pip_engine.py

@@ -14,174 +14,33 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Any
 
-logger = logging.getLogger(__name__)
-
-
-# ── 位置常量 ──────────────────────────────────────────────────────────────────
-
-# 9宫格位置枚举
-POSITION_TOP_LEFT = "top_left"
-POSITION_TOP_CENTER = "top_center"
-POSITION_TOP_RIGHT = "top_right"
-POSITION_CENTER_LEFT = "center_left"
-POSITION_CENTER = "center"
-POSITION_CENTER_RIGHT = "center_right"
-POSITION_BOTTOM_LEFT = "bottom_left"
-POSITION_BOTTOM_CENTER = "bottom_center"
-POSITION_BOTTOM_RIGHT = "bottom_right"
-
-_VALID_POSITIONS = {
-    POSITION_TOP_LEFT,
-    POSITION_TOP_CENTER,
-    POSITION_TOP_RIGHT,
-    POSITION_CENTER_LEFT,
-    POSITION_CENTER,
-    POSITION_CENTER_RIGHT,
-    POSITION_BOTTOM_LEFT,
-    POSITION_BOTTOM_CENTER,
-    POSITION_BOTTOM_RIGHT,
-}
-
-# 动画类型
-ANIMATION_FADE = "fade"  # 淡入淡出
-ANIMATION_SLIDE_LEFT = "slide_left"  # 从左滑入
-ANIMATION_SLIDE_RIGHT = "slide_right"  # 从右滑入
-ANIMATION_SLIDE_TOP = "slide_top"  # 从上滑入
-ANIMATION_SLIDE_BOTTOM = "slide_bottom"  # 从下滑入
-
-_VALID_ANIMATIONS = {
+from packages.domain.pip_config import (  # noqa: F401 — 向后兼容：保留模块级导出
     ANIMATION_FADE,
+    ANIMATION_SCALE,
+    ANIMATION_SLIDE_BOTTOM,
     ANIMATION_SLIDE_LEFT,
     ANIMATION_SLIDE_RIGHT,
     ANIMATION_SLIDE_TOP,
-    ANIMATION_SLIDE_BOTTOM,
-}
+    PiPConfig,
+    PiPLayerConfig,
+    POSITION_BOTTOM_LEFT,
+    POSITION_BOTTOM_RIGHT,
+    POSITION_CENTER,
+    POSITION_CENTER_LEFT,
+    POSITION_CENTER_RIGHT,
+    POSITION_TOP_CENTER,
+    POSITION_TOP_LEFT,
+    POSITION_TOP_RIGHT,
+    calculate_pip_position as _calculate_pip_position_base,
+    parse_size_value as _parse_size_value_base,
+)
 
+# 向后兼容：POSITION_BOTTOM_CENTER 也从 pip_config 再导出
+from packages.domain.pip_config import POSITION_BOTTOM_CENTER  # noqa: E402, F401
 
-# ── 数据模型 ──────────────────────────────────────────────────────────────────
-
-
-@dataclass
-class PiPLayerConfig:
-    """单个画中画图层配置."""
-
-    # 素材来源
-    source: str = ""  # 素材ID或视频URL
-    source_type: str = "asset_id"  # "asset_id" | "url" | "local_path"
-
-    # 位置配置
-    position: str = POSITION_BOTTOM_RIGHT  # 9宫格位置或 "custom"
-    x: int | str = 0  # 自定义x坐标（像素或百分比如 "30%"）
-    y: int | str = 0  # 自定义y坐标
-    margin: int = 20  # 9宫格模式下的边距（像素）
-
-    # 大小配置
-    width: int | str = "25%"  # 宽度（像素或百分比）
-    height: int | str = ""  # 高度（空则按比例自适应）
-
-    # 样式
-    opacity: float = 1.0  # 透明度 0.0-1.0
-    corner_radius: int = 0  # 圆角半径（像素），0表示无圆角
-    border_width: int = 0  # 边框宽度
-    border_color: str = "white"  # 边框颜色
-
-    # 时间控制
-    start_time: float = 0.0  # 开始显示时间（秒）
-    duration: float = 0.0  # 持续时长（秒），0表示全程显示
-
-    # 动画
-    animation_in: str = ""  # 入场动画类型
-    animation_out: str = ""  # 出场动画类型
-    animation_duration: float = 0.5  # 动画时长（秒）
-
-    # 层级
-    z_index: int = 1  # 图层顺序，数字越大越在上层
-
-    def validate(self) -> tuple[bool, str]:
-        """校验配置合法性，返回 (是否合法, 错误信息)."""
-        if not self.source:
-            return False, "source不能为空"
-
-        if self.position != "custom" and self.position not in _VALID_POSITIONS:
-            return False, f"无效的position: {self.position}"
-
-        if self.opacity < 0 or self.opacity > 1:
-            return False, "opacity必须在0-1之间"
-
-        if self.corner_radius < 0:
-            return False, "corner_radius不能为负数"
-
-        if self.start_time < 0:
-            return False, "start_time不能为负数"
-
-        if self.duration < 0:
-            return False, "duration不能为负数"
-
-        if self.animation_in and self.animation_in not in _VALID_ANIMATIONS:
-            return False, f"无效的入场动画: {self.animation_in}"
-
-        if self.animation_out and self.animation_out not in _VALID_ANIMATIONS:
-            return False, f"无效的出场动画: {self.animation_out}"
-
-        if self.animation_duration < 0:
-            return False, "animation_duration不能为负数"
-
-        return True, ""
-
-
-@dataclass
-class PiPConfig:
-    """画中画整体配置."""
-
-    enabled: bool = False
-    layers: list[PiPLayerConfig] = field(default_factory=list)
-
-    @classmethod
-    def from_dict(cls, data: dict[str, Any] | None) -> "PiPConfig":
-        """从字典解析配置."""
-        if not data or not data.get("enabled", False):
-            return cls(enabled=False)
-
-        layers_data = data.get("layers", [])
-        layers = []
-        for layer_data in layers_data:
-            try:
-                layer = PiPLayerConfig(
-                    source=layer_data.get("source", ""),
-                    source_type=layer_data.get("source_type", "asset_id"),
-                    position=layer_data.get("position", POSITION_BOTTOM_RIGHT),
-                    x=layer_data.get("x", 0),
-                    y=layer_data.get("y", 0),
-                    margin=int(layer_data.get("margin", 20)),
-                    width=layer_data.get("width", "25%"),
-                    height=layer_data.get("height", ""),
-                    opacity=float(layer_data.get("opacity", 1.0)),
-                    corner_radius=int(layer_data.get("corner_radius", 0)),
-                    border_width=int(layer_data.get("border_width", 0)),
-                    border_color=layer_data.get("border_color", "white"),
-                    start_time=float(layer_data.get("start_time", 0.0)),
-                    duration=float(layer_data.get("duration", 0.0)),
-                    animation_in=layer_data.get("animation_in", ""),
-                    animation_out=layer_data.get("animation_out", ""),
-                    animation_duration=float(layer_data.get("animation_duration", 0.5)),
-                    z_index=int(layer_data.get("z_index", 1)),
-                )
-                valid, err = layer.validate()
-                if valid:
-                    layers.append(layer)
-                else:
-                    logger.warning("PiP图层配置无效，跳过: %s", err)
-            except (ValueError, TypeError) as e:
-                logger.warning("PiP图层解析失败，跳过: %s", e)
-
-        # 按 z_index 排序
-        layers.sort(key=lambda layer: layer.z_index)
-
-        return cls(enabled=bool(layers), layers=layers)
+logger = logging.getLogger(__name__)
 
 
 # ── PiP 引擎 ──────────────────────────────────────────────────────────────────
@@ -201,16 +60,12 @@ class PiPEngine:
         self.output_fps = output_fps
 
     def _parse_size(self, value: int | str, base: int) -> int:
-        """解析尺寸值（像素或百分比）."""
-        if isinstance(value, int):
-            return max(1, value)
-        if isinstance(value, str) and value.endswith("%"):
-            pct = float(value.rstrip("%")) / 100.0
-            return max(1, int(base * pct))
-        try:
-            return max(1, int(value))
-        except (ValueError, TypeError):
-            return int(base * 0.25)  # 默认25%
+        """解析尺寸值（像素或百分比）.
+
+        委托给 packages.domain.pip_config.parse_size_value 纯逻辑函数，
+        薄包装保留在类内以维持向后兼容。
+        """
+        return _parse_size_value_base(value, base)
 
     def _parse_position(
         self,
@@ -218,28 +73,21 @@ class PiPEngine:
         pip_width: int,
         pip_height: int,
     ) -> tuple[int, int]:
-        """计算画中画的实际位置 (x, y)."""
-        W = self.output_width
-        H = self.output_height
-        m = layer.margin
+        """计算画中画的实际位置 (x, y).
 
-        if layer.position == "custom":
-            x = self._parse_size(layer.x, W)
-            y = self._parse_size(layer.y, H)
-            return (x, y)
-
-        pos_map = {
-            POSITION_TOP_LEFT: (m, m),
-            POSITION_TOP_CENTER: ((W - pip_width) // 2, m),
-            POSITION_TOP_RIGHT: (W - pip_width - m, m),
-            POSITION_CENTER_LEFT: (m, (H - pip_height) // 2),
-            POSITION_CENTER: ((W - pip_width) // 2, (H - pip_height) // 2),
-            POSITION_CENTER_RIGHT: (W - pip_width - m, (H - pip_height) // 2),
-            POSITION_BOTTOM_LEFT: (m, H - pip_height - m),
-            POSITION_BOTTOM_CENTER: ((W - pip_width) // 2, H - pip_height - m),
-            POSITION_BOTTOM_RIGHT: (W - pip_width - m, H - pip_height - m),
-        }
-        return pos_map.get(layer.position, pos_map[POSITION_BOTTOM_RIGHT])
+        委托给 packages.domain.pip_config.calculate_pip_position 纯逻辑函数，
+        薄包装保留在类内以维持向后兼容。
+        """
+        return _calculate_pip_position_base(
+            position=layer.position,
+            output_width=self.output_width,
+            output_height=self.output_height,
+            pip_width=pip_width,
+            pip_height=pip_height,
+            margin=layer.margin,
+            custom_x=layer.x,
+            custom_y=layer.y,
+        )
 
     def _build_pip_pre_filter(
         self,