Shotcut 26.2 update: new text options, subtitle search & crash fixes

Shotcut version 26.2 adds underline and strikethrough options for text filters and introduces a search field in the subtitles section. The release resolves several crashes, including those triggered by long video imports, the RGB Shift filter, FLAC export, and playlist actions with nothing selected. Windows users also benefit from fixes for video preview issues with HEVC sources and hardware decoding.