Problem: Premiere offers JPEG, Targa and DPX as image-sequence export
formats; FilmCraft only wrote PNG, TIFF and BMP sequences (docs/gaps.md G13).
Fix: three new export formats (ids jpg, tga, dpx), numbered like the other
sequences, with presets, the export UI (JPEG quality slider, Targa alpha)
and es/ja/zh-cn strings. JPEG uses the image crate at the export quality;
Targa (TGA 2.0, uncompressed 24/32-bit) and DPX (SMPTE ST 268, 10-bit RGB
method A, BT.709) are written by a small hostile-input-safe writer in
crates/export/src/raster.rs. Format::is_image_sequence replaces the
hand-kept format lists. OpenEXR stays open.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>