fix(overlay): thin centered trim handles and label-free subtitle boundaries in timing review (#274)

changes/timing-review-thin-handles.md

@@ -0,0 +1,5 @@
+type: fixed
+area: overlay
+
+- Media timing review trim handles are now thin lines centered on the clip edge, so it's clear where the clip starts and ends and less of the waveform is covered.
+- Original subtitle boundaries use orange bars without text tags, leaving the waveform unobstructed.