refactor(wave107): 抽离subtitle_style领域模型 + 76单测

- 从subtitle_render_engine.py抽离SubtitleStyle/SubtitleSegment/常量/ASS工具函数
- subtitle_render_engine保留全部导出，完全向后兼容
- 新增76个纯逻辑单测，覆盖颜色转换、时间格式化、文本换行、样式解析
- subtitle_render_engine.py: 685→454行 (-231行, -34%)

apps/worker/video_processing/subtitle_render_engine.py

@@ -24,264 +24,33 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass
 from pathlib import Path
-from typing import Any
 
+from packages.domain.subtitle_style import (  # noqa: F401  向后兼容导出
+    ALLOWED_SUBTITLE_EXTENSIONS,
+    DEFAULT_COLOR,
+    DEFAULT_FONT,
+    DEFAULT_FONT_SIZE,
+    DEFAULT_MAX_CHARS_PER_LINE,
+    DEFAULT_POSITION,
+    DEFAULT_STROKE_COLOR,
+    DEFAULT_STROKE_WIDTH,
+    POSITION_ALIGNMENT,
+    POSITION_ALIASES,
+    SubtitleSegment,
+    SubtitleStyle,
+    escape_ass_text as _escape_ass_text,
+    format_ass_time as _format_ass_time,
+    hex_to_ass_bgr as _hex_to_ass_bgr,
+    hex_to_ass_color as _hex_to_ass_color,
+    opacity_to_ass_alpha as _opacity_to_ass_alpha,
+    wrap_text as _wrap_text,
+)
 from video_processing.path_security import PathSecurityError, is_in_allowed_dirs, safe_resolve_path
 
 logger = logging.getLogger(__name__)
 
 
-# ── 常量 ──────────────────────────────────────────────────────────────────────
-
-ALLOWED_SUBTITLE_EXTENSIONS = {".srt", ".ass", ".vtt", ".sub"}
-
-# 9宫格位置映射（ASS alignment 编号）
-POSITION_ALIGNMENT = {
-    "top_left": 7,
-    "top_center": 8,
-    "top_right": 9,
-    "middle_left": 4,
-    "center": 5,
-    "middle_right": 6,
-    "bottom_left": 1,
-    "bottom_center": 2,
-    "bottom_right": 3,
-}
-
-# 位置简称兼容
-POSITION_ALIASES = {
-    "top": "top_center",
-    "bottom": "bottom_center",
-    "middle": "center",
-    "left": "middle_left",
-    "right": "middle_right",
-}
-
-DEFAULT_FONT = "思源黑体"
-DEFAULT_FONT_SIZE = 24
-DEFAULT_COLOR = "#FFFFFF"
-DEFAULT_STROKE_COLOR = "#000000"
-DEFAULT_STROKE_WIDTH = 1.5
-DEFAULT_POSITION = "bottom_center"
-DEFAULT_MAX_CHARS_PER_LINE = 20
-
-
-# ── 字幕样式配置 ────────────────────────────────────────────────────────────
-
-
-@dataclass
-class SubtitleStyle:
-    """字幕样式配置."""
-
-    font_name: str = DEFAULT_FONT
-    font_size: int = DEFAULT_FONT_SIZE
-    font_color: str = DEFAULT_COLOR
-    bold: bool = False
-    italic: bool = False
-
-    # 描边
-    stroke_enabled: bool = True
-    stroke_color: str = DEFAULT_STROKE_COLOR
-    stroke_width: float = DEFAULT_STROKE_WIDTH
-
-    # 阴影
-    shadow_enabled: bool = False
-    shadow_color: str = "#000000"
-    shadow_offset_x: int = 2
-    shadow_offset_y: int = 2
-    shadow_blur: float = 0.0
-
-    # 背景框
-    background_enabled: bool = False
-    background_color: str = "#000000"
-    background_opacity: float = 0.5  # 0.0 ~ 1.0
-    background_padding: int = 8
-    background_radius: int = 4
-
-    # 位置
-    position: str = DEFAULT_POSITION  # 9宫格位置名
-    margin_v: int = 60  # 垂直边距
-    margin_l: int = 40  # 左边距
-    margin_r: int = 40  # 右边距
-
-    # 多行
-    max_chars_per_line: int = DEFAULT_MAX_CHARS_PER_LINE
-    line_spacing: int = 0  # 行间距
-
-    # 动画
-    fade_in: float = 0.0  # 淡入时长（秒）
-    fade_out: float = 0.0  # 淡出时长（秒）
-    animation_type: str = "none"  # none/fade/slide/typewriter
-
-    @classmethod
-    def from_dict(cls, config: dict[str, Any] | None) -> "SubtitleStyle":
-        """从字典创建样式配置，带安全类型转换."""
-        if not config or not isinstance(config, dict):
-            return cls()
-
-        def safe_str(key: str, default: str) -> str:
-            val = config.get(key, default)
-            return str(val) if val is not None else default
-
-        def safe_int(key: str, default: int) -> int:
-            try:
-                return int(config.get(key, default))
-            except (TypeError, ValueError):
-                return default
-
-        def safe_float(key: str, default: float) -> float:
-            try:
-                return float(config.get(key, default))
-            except (TypeError, ValueError):
-                return default
-
-        def safe_bool(key: str, default: bool) -> bool:
-            return bool(config.get(key, default))
-
-        position = safe_str("position", DEFAULT_POSITION)
-        position = POSITION_ALIASES.get(position, position)
-        if position not in POSITION_ALIGNMENT:
-            position = DEFAULT_POSITION
-
-        return cls(
-            font_name=safe_str("font", DEFAULT_FONT),
-            font_size=safe_int("size", DEFAULT_FONT_SIZE),
-            font_color=safe_str("color", DEFAULT_COLOR),
-            bold=safe_bool("bold", False),
-            italic=safe_bool("italic", False),
-            stroke_enabled=safe_bool("stroke_enabled", True),
-            stroke_color=safe_str("stroke_color", DEFAULT_STROKE_COLOR),
-            stroke_width=safe_float("stroke_width", DEFAULT_STROKE_WIDTH),
-            shadow_enabled=safe_bool("shadow_enabled", False),
-            shadow_color=safe_str("shadow_color", "#000000"),
-            shadow_offset_x=safe_int("shadow_offset_x", 2),
-            shadow_offset_y=safe_int("shadow_offset_y", 2),
-            shadow_blur=safe_float("shadow_blur", 0.0),
-            background_enabled=safe_bool("background_enabled", False),
-            background_color=safe_str("background_color", "#000000"),
-            background_opacity=max(0.0, min(1.0, safe_float("background_opacity", 0.5))),
-            background_padding=safe_int("background_padding", 8),
-            background_radius=safe_int("background_radius", 4),
-            position=position,
-            margin_v=safe_int("margin_v", 60),
-            margin_l=safe_int("margin_l", 40),
-            margin_r=safe_int("margin_r", 40),
-            max_chars_per_line=safe_int("max_chars_per_line", DEFAULT_MAX_CHARS_PER_LINE),
-            line_spacing=safe_int("line_spacing", 0),
-            fade_in=max(0.0, safe_float("fade_in", 0.0)),
-            fade_out=max(0.0, safe_float("fade_out", 0.0)),
-            animation_type=safe_str("animation_type", "none"),
-        )
-
-    @property
-    def alignment(self) -> int:
-        """获取 ASS alignment 编号."""
-        return POSITION_ALIGNMENT.get(self.position, 2)
-
-    @property
-    def ass_font_color(self) -> str:
-        """ASS 格式颜色 &HAABBGGRR."""
-        return _hex_to_ass_color(self.font_color)
-
-    @property
-    def ass_stroke_color(self) -> str:
-        return _hex_to_ass_color(self.stroke_color)
-
-    @property
-    def ass_shadow_color(self) -> str:
-        return _hex_to_ass_color(self.shadow_color)
-
-    @property
-    def ass_background_color(self) -> str:
-        """背景框颜色（ASS BackColour），带透明度."""
-        alpha_hex = _opacity_to_ass_alpha(self.background_opacity)
-        color_bgr = _hex_to_ass_bgr(self.background_color)
-        return f"&H{alpha_hex}{color_bgr}"
-
-
-# ── 工具函数 ──────────────────────────────────────────────────────────────────
-
-
-def _hex_to_ass_color(hex_color: str) -> str:
-    """HEX → ASS 颜色 &HAABBGGRR（默认不透明）."""
-    hex_color = hex_color.lstrip("#")
-    if len(hex_color) != 6:
-        return "&H00FFFFFF"
-    r, g, b = hex_color[0:2], hex_color[2:4], hex_color[4:6]
-    return f"&H00{b.upper()}{g.upper()}{r.upper()}"
-
-
-def _hex_to_ass_bgr(hex_color: str) -> str:
-    """HEX → ASS BGR 部分（不含 alpha）."""
-    hex_color = hex_color.lstrip("#")
-    if len(hex_color) != 6:
-        return "FFFFFF"
-    r, g, b = hex_color[0:2], hex_color[2:4], hex_color[4:6]
-    return f"{b.upper()}{g.upper()}{r.upper()}"
-
-
-def _opacity_to_ass_alpha(opacity: float) -> str:
-    """不透明度 → ASS alpha（00=不透明，FF=完全透明）."""
-    alpha = 255 - int(opacity * 255)
-    return f"{alpha:02X}"
-
-
-def _escape_ass_text(text: str) -> str:
-    """转义 ASS 文本特殊字符."""
-    text = text.replace("\r\n", "\\N").replace("\n", "\\N").replace("\r", "\\N")
-    text = text.replace("{", "(").replace("}", ")")
-    return text
-
-
-def _format_ass_time(seconds: float) -> str:
-    """秒 → ASS 时间格式 H:MM:SS.cc."""
-    hours = int(seconds // 3600)
-    minutes = int((seconds % 3600) // 60)
-    secs = seconds % 60
-    return f"{hours}:{minutes:02d}:{secs:05.2f}"
-
-
-def _wrap_text(text: str, max_chars: int) -> list[str]:
-    """按字数换行，优先标点断开."""
-    if len(text) <= max_chars:
-        return [text]
-
-    lines: list[str] = []
-    remaining = text
-
-    while len(remaining) > max_chars:
-        break_point = max_chars
-        punctuations = "，。！？、；：,.;:!?"
-
-        for i in range(max_chars, max_chars // 2, -1):
-            if i < len(remaining) and remaining[i] in punctuations:
-                break_point = i + 1
-                break
-
-        lines.append(remaining[:break_point])
-        remaining = remaining[break_point:]
-
-    if remaining:
-        lines.append(remaining)
-
-    return lines
-
-
-# ── 字幕片段 ──────────────────────────────────────────────────────────────────
-
-
-@dataclass
-class SubtitleSegment:
-    """单个字幕片段."""
-
-    start: float  # 开始时间（秒）
-    end: float  # 结束时间（秒）
-    text: str  # 字幕文本
-    style_name: str = "Default"  # 使用的样式名
-
-
 # ── 字幕渲染引擎 ──────────────────────────────────────────────────────────────