🛡️ Sentinel: Enforce compressed block size limit

[kassoulet]

🛡️ Sentinel: Enforce compressed block size limit

Identified a potential resource exhaustion vulnerability where maliciously crafted bzip2 files could contain extremely large block ranges, leading to excessive memory allocation. Although the uncompressed size was already limited, the compressed range should also be bounded to ensure system stability.

Changes:

• Defined MAX_COMPRESSED_BLOCK_SIZE as 4MB in parallel_bzip2_decoder.
• Added Bz2Error::CompressedBlockLimitExceeded to the library's error type.
• Updated decompress_block_into to check the compressed byte length before processing.
• Updated bz2zstd's parallel worker loop to perform the same check before calling extract_bits.
• Added a unit test test_compressed_block_limit to verify the enforcement.

This is a defense-in-depth measure that complements the existing uncompressed block size limit.

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PR created automatically by Jules for task 15669133312938591188 started by @kassoulet

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