Adds AudioOperations.js with pure argument builders (convert/trim/extract/merge)
plus one executeOperation that spawns ffmpeg via a dependency-injected execFileFn,
so tests never invoke a real binary. Wires process-audio-operation in main.js and
updates preload.js's ALLOWED_SEND_CHANNELS to replace the 5 stale audio-* entries.
Amit Haridas
Three lines in tests/main/ImageOperations.test.js (copied verbatim
from the task brief's sample) exceeded the project's 100-char width,
failing npm run format:check. Ran npm run format to auto-fix; no
behavioral change.
Amit Haridas
Add src/main/ImageOperations.js (convert/resize/compress/rotate via
sharp), modeled on PDFOperations.js's executeOperation dispatcher.
Wire ipcMain.handle('process-image-operation', ...) in main.js using
sanitizeErrorMessage() on error paths, and replace the 5 stale/unused
image-* channel names in preload.js's ALLOWED_SEND_CHANNELS with
process-image-operation + select-image-folder (mirroring
select-pdf-folder for a later batch-UI task).
Amit Haridas
amitwh