fix(subtitles): follow sub-delay in sidebar, navigation, and overlay matching

Anything comparing time-pos with parsed cues now converts through a
shared subtitle-clock helper: the sidebar highlight and click-to-seek,
the sub-seek cue sanitizer, overlay/primer line resolution, and the
replay pause point after sub-seek.

src/core/services/mining.ts

@@ -1,5 +1,6 @@
 import type { SubtitleTimingBlock } from '../../subtitle-timing-tracker';
 import type { SubtitleMiningContext } from '../../types/subtitle';
+import { shiftSubtitleRangeToVideoClock } from './subtitle-clock';
 
 interface SubtitleTimingTrackerLike {
   getRecentBlocks: (count: number) => string[];
@@ -56,21 +57,6 @@ export function handleMultiCopyDigit(
   }
 }
 
-/**
- * mpv's `sub-start`/`sub-end` and parsed cues carry the subtitle file's own timestamps,
- * but mpv plays each line `sub-delay` seconds later (z/x retiming). Media is cut from the
- * video, so subtitle timings move onto the video clock before they reach mining.
- */
-export function shiftSubtitleRangeToVideoClock<T extends { startTime: number; endTime: number }>(
-  range: T,
-  subDelay: number,
-): T {
-  if (!Number.isFinite(subDelay) || subDelay === 0) {
-    return range;
-  }
-  return { ...range, startTime: range.startTime + subDelay, endTime: range.endTime + subDelay };
-}
-
 /**
  * Snapshot the live mpv subtitle line and its timings as a mining context. Media
  * generation can run tens of seconds after the user mines (slow audio extraction),