fix(events): scrub with seek alone, no pause/play wrapper

Each scrub gesture sent CMD_PAUSE on grab and CMD_PLAY on release around the
CMD_SEEK. Those three unordered requests raced and were unnecessary: ZMS handles
a seek without bracketing it, so a single CMD_SEEK per position is enough. Drop
the pause/resume; the scrub-start/end handlers now only gate the status poll so
it does not overwrite the playhead mid-drag.

refs #196

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: pliablepixels

app/src/components/events/ZmsEventPlayer.tsx

@@ -79,10 +79,8 @@ export function ZmsEventPlayer({
 
   // While the user drags the scrub bar, the status poll must not write the
   // playhead back from the stream: that fight makes the cursor and video jump
-  // around mid-drag (refs #196). The grab also pauses the stream so it does not
-  // play forward between seeks. wasPlayingRef remembers whether to resume.
+  // around mid-drag (refs #196). Each scrub position is sent as a CMD_SEEK.
   const isScrubbingRef = useRef(false);
-  const wasPlayingRef = useRef(false);
 
   // Unique connection key for this stream, stable for the component's lifetime.
   // Speed changes are sent as CMD_VARPLAY over this same connkey instead of
@@ -323,19 +321,17 @@ export function ZmsEventPlayer({
     goToFrame(totalFrames);
   }, [goToFrame, totalFrames]);
 
-  // Grab the scrub bar: pause the stream so it shows a single still frame per
-  // seek instead of playing forward between drags, and silence the status poll.
+  // Grab the scrub bar: just silence the status poll so it does not write the
+  // playhead back mid-drag. Each scrub position is a CMD_SEEK; ZMS handles the
+  // seek without a surrounding pause/play, so we do not send them (refs #196).
   const handleScrubStart = useCallback(() => {
     isScrubbingRef.current = true;
-    wasPlayingRef.current = isPlaying;
-    if (isPlaying) sendCommand(ZMS_COMMANDS.cmdPause);
-  }, [isPlaying, sendCommand]);
+  }, []);
 
-  // Release: resume playback only if it was playing when the drag began.
+  // Release: re-enable the status poll. Playback state is unchanged by scrubbing.
   const handleScrubEnd = useCallback(() => {
     isScrubbingRef.current = false;
-    if (wasPlayingRef.current) sendCommand(ZMS_COMMANDS.cmdPlay);
-  }, [sendCommand]);
+  }, []);
 
   // Jump to alarm frame
   const jumpToAlarmFrame = useCallback(() => {

app/src/components/events/__tests__/ZmsEventPlayer.test.tsx

@@ -19,6 +19,7 @@ vi.mock('react-i18next', () => ({
 vi.mock('../../../lib/logger', () => ({
   log: {
     zmsEventPlayer: vi.fn(),
+    eventProgressBar: vi.fn(),
   },
   LogLevel: {
     DEBUG: 0,
@@ -155,19 +156,21 @@ describe('ZmsEventPlayer', () => {
     expect(new URL(seek![0] as string).searchParams.get('offset')).toBe('20');
   });
 
-  it('pauses the stream while scrubbing and resumes playing on release', () => {
+  it('scrubs with seek alone, without pausing or resuming the stream', () => {
     renderPlayer();
     fireEvent.load(getStreamImg());
     const track = stubTrack();
 
-    // Grabbing the scrub bar pauses the running stream (CMD_PAUSE = 1) so the
-    // video does not play forward between seeks.
+    // Grabbing/moving the scrub bar issues a seek (CMD_SEEK = 14)...
     fireEvent.mouseDown(track, { clientX: 100 });
-    expect(callsForCommand('1').length).toBeGreaterThan(0);
+    expect(callsForCommand('14').length).toBeGreaterThan(0);
 
-    // Releasing resumes playback (CMD_PLAY = 2).
     fireEvent.mouseUp(window);
-    expect(callsForCommand('2').length).toBeGreaterThan(0);
+
+    // ...but never pauses (CMD_PAUSE = 1) or resumes (CMD_PLAY = 2): the seek
+    // drives playback by itself (refs #196).
+    expect(callsForCommand('1')).toHaveLength(0);
+    expect(callsForCommand('2')).toHaveLength(0);
   });
 
   it('keeps the img src and connkey unchanged when playback speed changes', () => {