diff --git a/apps/api/app/services/ai_service.py b/apps/api/app/services/ai_service.py
index 13e465b2f..6e1291a11 100755
--- a/apps/api/app/services/ai_service.py
+++ b/apps/api/app/services/ai_service.py
@@ -12,7 +12,6 @@
 
 from __future__ import annotations
 
-import json
 import logging
 from typing import Any, Dict, List, Optional
 
diff --git a/apps/worker/video_processing/chroma_key_engine.py b/apps/worker/video_processing/chroma_key_engine.py
index 7499b2f61..d95df928f 100755
--- a/apps/worker/video_processing/chroma_key_engine.py
+++ b/apps/worker/video_processing/chroma_key_engine.py
@@ -9,12 +9,11 @@
 from __future__ import annotations
 
 import logging
-from typing import Optional
 
+from packages.domain.chroma_key_config import CHROMA_KEY_PRESETS  # noqa: F401
+from packages.domain.chroma_key_config import apply_chroma_key_if_needed  # noqa: F401
 from packages.domain.chroma_key_config import (
-    CHROMA_KEY_PRESETS,
     ChromaKeyConfig,
-    apply_chroma_key_if_needed,
 )
 from packages.domain.chroma_key_config import (  # noqa: F401 — 向后兼容
     build_chromakey_filter as _build_chromakey_filter_base,
diff --git a/apps/worker/video_processing/color_grade_engine.py b/apps/worker/video_processing/color_grade_engine.py
index da5b44d8d..9fb367373 100755
--- a/apps/worker/video_processing/color_grade_engine.py
+++ b/apps/worker/video_processing/color_grade_engine.py
@@ -195,17 +195,3 @@ class ColorGradeEngine:
 
 
 # ── 便捷函数 ──────────────────────────────────────────────────────────────────
-
-
-def get_preset_names() -> list[tuple[str, str]]:
-    """获取所有预设名称列表.
-
-    Returns:
-        [(preset_key, display_name), ...]
-    """
-    return [(key, PRESET_DISPLAY_NAMES.get(key, key)) for key in PRESET_PARAMS.keys()]
-
-
-def get_preset_params(preset: str) -> dict[str, float] | None:
-    """获取指定预设的参数."""
-    return PRESET_PARAMS.get(preset)
diff --git a/apps/worker/video_processing/ffmpeg_utils.py b/apps/worker/video_processing/ffmpeg_utils.py
index 6cac1228b..9436c489f 100755
--- a/apps/worker/video_processing/ffmpeg_utils.py
+++ b/apps/worker/video_processing/ffmpeg_utils.py
@@ -22,11 +22,9 @@ from shared.ffmpeg_utils import (  # noqa: F401
 
 # xfade 转场纯逻辑已抽离到 domain 层，这里 re-export 保持向后兼容
 from packages.domain.xfade_builder import DEFAULT_TRANSITION_DURATION as _default_transition_duration_base  # noqa: F401
-from packages.domain.xfade_builder import (
-    SUPPORTED_TRANSITIONS,
-    XFADE_TRANSITION_MAP,
-    XFade_TRANSITION_NAMES,
-)
+from packages.domain.xfade_builder import SUPPORTED_TRANSITIONS  # noqa: F401
+from packages.domain.xfade_builder import XFADE_TRANSITION_MAP  # noqa: F401
+from packages.domain.xfade_builder import XFade_TRANSITION_NAMES  # noqa: F401
 from packages.domain.xfade_builder import build_xfade_filter_chain as _build_xfade_filter_chain_base
 from packages.domain.xfade_builder import chain_filters as _chain_filters_base
 from packages.domain.xfade_builder import resolve_xfade_transition as _resolve_xfade_transition_base
diff --git a/apps/worker/video_processing/noise_reduction_engine.py b/apps/worker/video_processing/noise_reduction_engine.py
index e55220d62..e8db5bb64 100755
--- a/apps/worker/video_processing/noise_reduction_engine.py
+++ b/apps/worker/video_processing/noise_reduction_engine.py
@@ -9,16 +9,21 @@ from __future__ import annotations
 
 import logging
 
+# isort: off
 from packages.domain.noise_reduction_config import (
     NoiseReductionConfig,
-    NoiseReductionLevel,
+    NoiseReductionLevel,  # noqa: F401
 )
 from packages.domain.noise_reduction_config import (
     apply_noise_reduction_if_needed as _apply_noise_reduction_if_needed_base,
 )
-from packages.domain.noise_reduction_config import build_afftdn_filter as _build_afftdn_filter_base  # noqa: F401 — 向后兼容
+from packages.domain.noise_reduction_config import (
+    build_afftdn_filter as _build_afftdn_filter_base,
+)  # noqa: F401 — 向后兼容
 from packages.domain.noise_reduction_config import build_arnndn_filter as _build_arnndn_filter_base
 
+# isort: on
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/apps/worker/video_processing/pip_engine.py b/apps/worker/video_processing/pip_engine.py
index 74733853a..e4e2d3feb 100755
--- a/apps/worker/video_processing/pip_engine.py
+++ b/apps/worker/video_processing/pip_engine.py
@@ -18,22 +18,13 @@ from pathlib import Path
 
 # 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
+from packages.domain.pip_config import PiPConfig  # noqa: F401
 from packages.domain.pip_config import (
     ANIMATION_FADE,
-    ANIMATION_SCALE,
     ANIMATION_SLIDE_BOTTOM,
     ANIMATION_SLIDE_LEFT,
     ANIMATION_SLIDE_RIGHT,
     ANIMATION_SLIDE_TOP,
-    POSITION_BOTTOM_LEFT,
-    POSITION_BOTTOM_RIGHT,
-    POSITION_CENTER,
-    POSITION_CENTER_LEFT,
-    POSITION_CENTER_RIGHT,
-    POSITION_TOP_CENTER,
-    POSITION_TOP_LEFT,
-    POSITION_TOP_RIGHT,
-    PiPConfig,
     PiPLayerConfig,
 )
 from packages.domain.pip_config import (  # noqa: F401 — 向后兼容：保留模块级导出
diff --git a/apps/worker/video_processing/render_subtitles.py b/apps/worker/video_processing/render_subtitles.py
index 9b8f58e63..06c780463 100755
--- a/apps/worker/video_processing/render_subtitles.py
+++ b/apps/worker/video_processing/render_subtitles.py
@@ -13,9 +13,6 @@ from pathlib import Path
 from typing import Any
 
 from packages.domain.ass_subtitle_builder import (
-    TITLE_MARGIN_BOTTOM,
-    TITLE_MARGIN_SIDE,
-    TITLE_MARGIN_TOP,
     build_ass_content,
 )
 from packages.domain.ass_subtitle_builder import build_ass_style as _build_ass_style_base  # noqa: F401 — 向后兼容
diff --git a/apps/worker/video_processing/sticker_engine.py b/apps/worker/video_processing/sticker_engine.py
index 131287b0e..148c88963 100755
--- a/apps/worker/video_processing/sticker_engine.py
+++ b/apps/worker/video_processing/sticker_engine.py
@@ -14,16 +14,20 @@ import logging
 from pathlib import Path
 from typing import Any
 
+# isort: off
 from packages.domain.sticker_config import (
-    POSITION_PRESETS,
-    STICKER_CATEGORIES,
+    POSITION_PRESETS,  # noqa: F401
+    STICKER_CATEGORIES,  # noqa: F401
     ImageStickerConfig,
     StickerOverlayResult,
     TextStickerConfig,
 )
-from packages.domain.sticker_config import get_sticker_categories as _get_sticker_categories_base  # noqa: F401  向后兼容导出
+from packages.domain.sticker_config import (
+    get_sticker_categories as _get_sticker_categories_base,
+)  # noqa: F401  向后兼容导出
 from packages.domain.sticker_config import parse_stickers_from_config as _parse_stickers_base
 from packages.domain.sticker_config import (
+    # isort: on
     resolve_sticker_position,
 )
 
diff --git a/apps/worker/video_processing/subtitle_render_engine.py b/apps/worker/video_processing/subtitle_render_engine.py
index a227205aa..f37f8ba6f 100755
--- a/apps/worker/video_processing/subtitle_render_engine.py
+++ b/apps/worker/video_processing/subtitle_render_engine.py
@@ -25,28 +25,22 @@ from __future__ import annotations
 
 import logging
 from pathlib import Path
+from typing import Any
 
 from video_processing.path_security import PathSecurityError, is_in_allowed_dirs, safe_resolve_path
 
 from packages.domain.subtitle_style import (
     ALLOWED_SUBTITLE_EXTENSIONS,
-    DEFAULT_COLOR,
-    DEFAULT_FONT,
     DEFAULT_FONT_SIZE,
-    DEFAULT_MAX_CHARS_PER_LINE,
     DEFAULT_POSITION,
-    DEFAULT_STROKE_COLOR,
-    DEFAULT_STROKE_WIDTH,
-    POSITION_ALIASES,
-    POSITION_ALIGNMENT,
     SubtitleSegment,
     SubtitleStyle,
 )
 from packages.domain.subtitle_style import escape_ass_text as _escape_ass_text  # noqa: F401  向后兼容导出
 from packages.domain.subtitle_style import format_ass_time as _format_ass_time
-from packages.domain.subtitle_style import hex_to_ass_bgr as _hex_to_ass_bgr
-from packages.domain.subtitle_style import hex_to_ass_color as _hex_to_ass_color
-from packages.domain.subtitle_style import opacity_to_ass_alpha as _opacity_to_ass_alpha
+from packages.domain.subtitle_style import hex_to_ass_bgr as _hex_to_ass_bgr  # noqa: F401
+from packages.domain.subtitle_style import hex_to_ass_color as _hex_to_ass_color  # noqa: F401
+from packages.domain.subtitle_style import opacity_to_ass_alpha as _opacity_to_ass_alpha  # noqa: F401
 from packages.domain.subtitle_style import wrap_text as _wrap_text
 
 logger = logging.getLogger(__name__)
diff --git a/apps/worker/video_processing/trim_engine.py b/apps/worker/video_processing/trim_engine.py
index 5e3a78ec6..6b9417de5 100755
--- a/apps/worker/video_processing/trim_engine.py
+++ b/apps/worker/video_processing/trim_engine.py
@@ -15,16 +15,14 @@ from __future__ import annotations
 import logging
 from typing import Any
 
+from packages.domain.trim_config import MIN_TRIM_DURATION  # noqa: F401
+from packages.domain.trim_config import extract_trim_from_clip_config  # noqa: F401
 from packages.domain.trim_config import (
-    MIN_TRIM_DURATION,
     TrimConfig,
     TrimSegment,
 )
 from packages.domain.trim_config import build_audio_trim_filter as _build_audio_trim_filter  # noqa: F401 — 向后兼容
 from packages.domain.trim_config import build_video_trim_filter as _build_video_trim_filter
-from packages.domain.trim_config import (
-    extract_trim_from_clip_config,
-)
 from packages.domain.trim_config import parse_segments_from_config as _parse_segments_from_config
 from packages.domain.trim_config import resolve_segments as _resolve_segments
 
diff --git a/apps/worker/video_processing/unified_render_service.py b/apps/worker/video_processing/unified_render_service.py
index 3a35dda9a..c8f6229c8 100755
--- a/apps/worker/video_processing/unified_render_service.py
+++ b/apps/worker/video_processing/unified_render_service.py
@@ -53,7 +53,6 @@ from video_processing.tts_engine import TtsEngine
 from video_processing.watermark_engine import WatermarkConfig, WatermarkEngine
 
 from packages.domain.render_layer_utils import LAYER_Z_INDEX as _IMPORTED_LAYER_Z_INDEX
-from packages.domain.render_layer_utils import can_pass_through as _can_pass_through_pure
 from packages.domain.render_layer_utils import clip_adjusted_duration as _clip_adjusted_duration_pure
 from packages.domain.render_layer_utils import clip_effective_duration as _clip_effective_duration_pure
 from packages.domain.render_layer_utils import clip_playback_speed as _clip_playback_speed_pure
diff --git a/apps/worker/video_processing/watermark_engine.py b/apps/worker/video_processing/watermark_engine.py
index 797571b33..c92f3bb6a 100755
--- a/apps/worker/video_processing/watermark_engine.py
+++ b/apps/worker/video_processing/watermark_engine.py
@@ -14,10 +14,9 @@
 from __future__ import annotations
 
 import logging
-from typing import Any
 
+from packages.domain.watermark_config import WATERMARK_POSITIONS  # noqa: F401
 from packages.domain.watermark_config import (
-    WATERMARK_POSITIONS,
     WatermarkConfig,
 )
 from packages.domain.watermark_config import (  # noqa: F401 — 向后兼容
diff --git a/packages/domain/pip_config.py b/packages/domain/pip_config.py
index e843504cb..522d696a9 100755
--- a/packages/domain/pip_config.py
+++ b/packages/domain/pip_config.py
@@ -186,7 +186,7 @@ class PiPConfig:
         """最大 z_index."""
         if not self.layers:
             return 0
-        return max(l.z_index for l in self.layers)
+        return max(layer.z_index for layer in self.layers)
 
 
 # ── 纯逻辑工具函数 ───────────────────────────────────────────────────────────
diff --git a/packages/domain/subtitle_style.py b/packages/domain/subtitle_style.py
index 481e0d83c..293f684ab 100755
--- a/packages/domain/subtitle_style.py
+++ b/packages/domain/subtitle_style.py
@@ -6,7 +6,7 @@
 
 from __future__ import annotations
 
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any
 
 # ── 常量 ──────────────────────────────────────────────────────────────────────
diff --git a/packages/domain/trim_config.py b/packages/domain/trim_config.py
index 2cf912390..dee801748 100755
--- a/packages/domain/trim_config.py
+++ b/packages/domain/trim_config.py
@@ -11,7 +11,7 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any
 
 logger = logging.getLogger(__name__)
diff --git a/packages/domain/watermark_config.py b/packages/domain/watermark_config.py
index 5aa05b47d..3373b317b 100755
--- a/packages/domain/watermark_config.py
+++ b/packages/domain/watermark_config.py
@@ -10,7 +10,7 @@
 from __future__ import annotations
 
 import logging
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import Any
 
 logger = logging.getLogger(__name__)
diff --git a/tests/unit/test_color_grade_config.py b/tests/unit/test_color_grade_config.py
index 0bc89a985..0af8a336d 100755
--- a/tests/unit/test_color_grade_config.py
+++ b/tests/unit/test_color_grade_config.py
@@ -39,7 +39,7 @@ class TestConstants:
 
     def test_preset_params_complete(self):
         assert set(PRESET_PARAMS.keys()) == VALID_PRESETS
-        for preset, params in PRESET_PARAMS.items():
+        for _preset, params in PRESET_PARAMS.items():
             assert set(params.keys()) == set(ALL_PARAM_KEYS)
 
     def test_default_params_keys(self):
@@ -54,7 +54,7 @@ class TestConstants:
             assert min_val <= DEFAULT_PARAMS[key] <= max_val
 
     def test_all_presets_within_ranges(self):
-        for preset, params in PRESET_PARAMS.items():
+        for _preset, params in PRESET_PARAMS.items():
             for key in ALL_PARAM_KEYS:
                 min_val, max_val = PARAM_RANGES[key]
                 assert min_val <= params[key] <= max_val, f"{preset}.{key}={params[key]} out of range"
diff --git a/tests/unit/test_pip_config.py b/tests/unit/test_pip_config.py
index 6249b0e33..c2deafd2d 100755
--- a/tests/unit/test_pip_config.py
+++ b/tests/unit/test_pip_config.py
@@ -208,7 +208,7 @@ class TestPiPConfigFromDict:
             }
         )
         assert cfg.layer_count == 3
-        assert [l.source for l in cfg.layers] == ["bottom", "mid", "top"]
+        assert [layer.source for layer in cfg.layers] == ["bottom", "mid", "top"]
 
     def test_invalid_layer_skipped(self):
         cfg = PiPConfig.from_dict(
diff --git a/tests/unit/test_sticker_config.py b/tests/unit/test_sticker_config.py
index b42b2ea6b..e6048abc9 100755
--- a/tests/unit/test_sticker_config.py
+++ b/tests/unit/test_sticker_config.py
@@ -23,7 +23,7 @@ class TestConstants:
         assert len(POSITION_PRESETS) == 9
 
     def test_position_presets_normalized(self):
-        for name, (x, y) in POSITION_PRESETS.items():
+        for _name, (x, y) in POSITION_PRESETS.items():
             assert 0.0 <= x <= 1.0
             assert 0.0 <= y <= 1.0