feat: Major fragmented mp4 optimisation #5027

Job	Run time
Detect Changes	7s
Format (Cargo)	14s
Lint (Biome)	11s
Format (Biome)	7s
Typecheck	1m 11s
Clippy (aarch64-apple-darwin, macos-latest)	2m 2s
Clippy (x86_64-pc-windows-msvc, windows-latest)	4m 10s
Verify Tauri plugin versions	0s
Build Desktop	0s
Rust cache	0s
	8m 2s

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