Fix three bugs in the subtitle resync tool

[Nawid3333]

What breaks

Three bugs in the subtitle resync tool, all user-visible:

1. The whole track is redrawn every frame. renderTracks() picked the
   cues to draw with

   return cue.startTime <= maxTime || cue.endTime >= minTime;

   which is true for every cue: any cue starts before the right edge
   (start <= max) or ends after the left edge (end >= min). The
   intended window test is the conjunction - cues that overlap the visible
   range - so the entire track stayed in the DOM and every cue was
   repositioned on every frame, instead of only the handful on screen.

2. Every shift key press threw a TypeError. shiftSubtitles() called
   this.onVideoTimeUpdate(), a method SubtitleSyncer does not have. The
   EventEmitter caught and logged it, so the shift still applied, but the
   console filled with

   TypeError: this.onVideoTimeUpdate is not a function
   

3. A right-click started a drag. The track started grabbing on any
   mouse button. After a right-click, the context menu swallows the
   mouseup, so the track kept following the pointer with no button held.

The fix

• Filter with && - the cues that overlap the visible window:

  return cue.startTime <= maxTime && cue.endTime >= minTime;

• Drop the call to the method that does not exist. The timeline redraws on
  its own; the cues in view are refreshed immediately instead:
  this.lastUpdate = 0 (the render throttle) before re-rendering.

• Left button only, as the time ticks in the same UI already do:
  if (e.button !== 0) return;

• After a keyboard shift, lastUpdate = 0 also makes cues that moved into
  view appear right away instead of up to 500 ms later.

Diff: 1 file, 8 insertions, 2 deletions.

Why this can't break anything else

• Blast radius of the file: SubtitleSyncer.mjs is the resync tool's
  own controller, instantiated only when the subtitle-resync UI is open.
  Normal subtitle playback (SubtitlesManager) does not run this code.
• Change 1 is a pure filter correction: the same cues used to be drawn
  every frame; now only the overlapping ones are. A cue either overlapped
  the window or it did not - || included all of them, && includes
  exactly the intended set. Cues outside the window were invisible anyway;
  they were just kept in the DOM.
• Change 2 removes a call to a method that does not exist - there is no
  behavior to preserve. The redraw it was meant to trigger is covered by
  lastUpdate = 0 on the next render tick, which is the file's own
  throttle mechanism.
• Change 3 restricts an input from "any button" to "left button only" -
  strictly fewer grab starts, and the tick marks elsewhere in the same UI
  already used the identical guard.

Verification

• Build: npm ci + node localescript.mjs + node build.mjs (this
  repo's own build path) - all three targets build.
• Each fix exercised: cue window - a track whose cues straddle the
  visible range now renders only overlapping cues; shift keys - no
  TypeError in the console, cues repositioned immediately; right-click on
  the track - context menu opens, no drag follows.
• Lint: eslint with this repo's .eslintrc.js (google config): no
  problems.
• Diff shape: git diff --numstat against main:
  8 2 chrome/player/ui/subtitles/SubtitleSyncer.mjs.