Add jbrd box support for JPEG reconstruction

[hjanuschka]

Summary

• Add bit-exact JPEG reconstruction from jbrd boxes, including Huffman tables, scans, marker order, and APP markers
• Preserve and pipe VarDCT quantized coefficients through decode to reconstruction output
• Use codestream quant tables, ICC data, and sampling factors when writing JPEG; handle subsampled component block grids
• Feature is behind the jpeg-reconstruction flag and is off by default

[hjanuschka]

@veluca93 eventhough you dont want to merge it, it would be now feature complete, lets keep it around and mergeable in case you change your mind.

[github-actions]

Benchmark @ 30ebc6d

MULTI-FILE BENCHMARK RESULTS (4 files)
  CPU architecture: x86_64
  WARNING: System appears noisy: high system load (2.26). Results may be unreliable.
Statistics:
  Confidence:               99.0%
  Max relative error:        3.0%

Comparing: 90a2bb2a (Base) vs 45d6dc39 (PR)

File	Base (MP/s)	PR (MP/s)	Δ%
bike.jxl	25.270	24.605	-2.63% ±2.8%
green_queen_modular_e3.jxl	7.918	7.870	-0.60% ±0.4%
green_queen_vardct_e3.jxl	23.329	23.318	-0.05% ±1.1%
sunset_logo.jxl	2.245	2.213	-1.45% ±0.6%

[zone117x]

@hjanuschka @veluca93 are there any blockers on this PR? This is a useful feature that I would like to use.

I'm happy to help contribute if needed, although it looks like @hjanuschka is pretty on top of things :)