Formats seconds for display inside an editable trim timestamp field.
Uses YouTube-style H:MM:SS / M:SS labels; fractional values keep colons
(1:33:15.867) so editing matches the read-only display instead of raw seconds.
Parameters
seconds: number
Timestamp in seconds.
Returns string
String suitable for pre-filling a trim time input.
Formats seconds for display inside an editable trim timestamp field. Uses YouTube-style
H:MM:SS/M:SSlabels; fractional values keep colons (1:33:15.867) so editing matches the read-only display instead of raw seconds.